1 00:00:00,900 --> 00:00:04,700 ♪♪ 2 00:00:06,000 --> 00:00:09,933 -The Roman Empire stretched from Hadrian's Wall in Britain 3 00:00:09,933 --> 00:00:12,700 east to Babylonia, in present-day Iraq, 4 00:00:12,700 --> 00:00:16,233 and across the northern coast of Africa. 5 00:00:16,233 --> 00:00:18,200 Expanding and contracting, 6 00:00:18,200 --> 00:00:21,566 the empire lasted nearly 1,000 years, 7 00:00:21,566 --> 00:00:23,433 influencing politics, art, 8 00:00:23,433 --> 00:00:26,900 and architecture for millennia to come. 9 00:00:26,900 --> 00:00:29,666 Historians and archaeologists have long theorized 10 00:00:29,666 --> 00:00:33,900 about what caused the collapse of such a powerful civilization. 11 00:00:33,900 --> 00:00:36,733 Did surrounding enemies become more ruthless 12 00:00:36,733 --> 00:00:40,133 while Roman emperors lost their ability to lead 13 00:00:40,133 --> 00:00:43,600 or was it something far beyond the control of any emperor 14 00:00:43,600 --> 00:00:44,966 or military leader? 15 00:00:48,566 --> 00:00:52,100 Today, archaeologists and scientists speculate 16 00:00:52,100 --> 00:00:54,466 that a series of virulent pandemics 17 00:00:54,466 --> 00:00:56,100 took their toll on the mighty realm. 18 00:00:58,000 --> 00:01:01,033 New scientific advances have allowed researchers 19 00:01:01,033 --> 00:01:03,300 to identify the pathogens responsible 20 00:01:03,300 --> 00:01:08,100 for decimating Ancient Rome's population. 21 00:01:08,100 --> 00:01:10,933 Did mass disease weaken the military 22 00:01:10,933 --> 00:01:15,133 and allow adversaries their first victories? 23 00:01:15,133 --> 00:01:17,400 Or were other forces involved? 24 00:01:19,366 --> 00:01:23,066 Centuries of climate data from all over Europe and Russia 25 00:01:23,066 --> 00:01:25,166 has shown how the climate changed 26 00:01:25,166 --> 00:01:27,033 across the empire. 27 00:01:27,033 --> 00:01:30,633 How would a sudden temperature drop have affected 28 00:01:30,633 --> 00:01:32,300 the health of Rome's inhabitants? 29 00:01:35,466 --> 00:01:38,266 Cooling temperatures likely provoked 30 00:01:38,266 --> 00:01:39,866 the great westward migrations 31 00:01:39,866 --> 00:01:42,633 that changed the history of Europe 32 00:01:42,633 --> 00:01:45,933 and brought Rome into conflict with numerous groups. 33 00:01:49,800 --> 00:01:53,033 And then, at a moment when it seemed the empire 34 00:01:53,033 --> 00:01:55,733 might return to its former glory, 35 00:01:55,733 --> 00:02:00,433 the emperor's troops failed to reconquer lost territories. 36 00:02:02,466 --> 00:02:06,900 Could a violent natural disaster be the real reason Rome fell? 37 00:02:09,866 --> 00:02:13,100 What destroyed one of the most powerful civilizations 38 00:02:13,100 --> 00:02:14,600 in history? 39 00:02:14,600 --> 00:02:25,400 ♪♪ 40 00:02:27,733 --> 00:02:31,200 ♪♪ 41 00:02:31,200 --> 00:02:33,666 -The decline of Rome begins several centuries 42 00:02:33,666 --> 00:02:36,766 before the empire actually falls. 43 00:02:36,766 --> 00:02:42,466 In the year 165 A.D., two men lead the vast dominion -- 44 00:02:42,466 --> 00:02:46,600 Marcus Aurelius and Lucius Verus. 45 00:02:46,600 --> 00:02:50,200 That year, Marcus stayed in Rome, 46 00:02:50,200 --> 00:02:55,600 while Lucius left to fight the Parthian Empire in the East. 47 00:02:55,600 --> 00:02:58,466 Rome is victorious over the Parthians, 48 00:02:58,466 --> 00:03:01,566 but in the coming years, many in the empire wonder 49 00:03:01,566 --> 00:03:06,266 whether an excess of violence brought disfavor from the gods. 50 00:03:08,400 --> 00:03:12,400 Rome takes control of the Parthian capital city, Seleucia, 51 00:03:12,400 --> 00:03:14,866 which is located on the Tigris River 52 00:03:14,866 --> 00:03:19,233 and is home to an important temple to Apollo. 53 00:03:19,233 --> 00:03:22,966 Initially, Roman troops enter the city peacefully, 54 00:03:22,966 --> 00:03:27,600 but then looting begins. 55 00:03:27,600 --> 00:03:30,900 -So, it was the year 165, after four years of war 56 00:03:30,900 --> 00:03:34,233 between Romans and Parthians, in the disputed Middle East. 57 00:03:36,466 --> 00:03:38,800 The victories achieved by the Romans 58 00:03:38,800 --> 00:03:41,033 gave them access to Mesopotamia, 59 00:03:41,033 --> 00:03:43,033 and they were able to sail in several columns 60 00:03:43,033 --> 00:03:45,366 down the Euphrates and Tigris rivers, 61 00:03:45,366 --> 00:03:48,200 to the heart of Babylonia, where the large capitals 62 00:03:48,200 --> 00:03:49,866 of the Parthian Empire were located. 63 00:03:54,366 --> 00:03:56,633 The largest one was Seleucia-on-Tigris, 64 00:03:56,633 --> 00:04:00,900 a huge city with hundreds of thousands of inhabitants, 65 00:04:00,900 --> 00:04:02,700 the equivalent of Rome or Alexandria 66 00:04:02,700 --> 00:04:04,866 from the Parthians' point of view. 67 00:04:04,866 --> 00:04:07,033 Although it was a cosmopolitan city, 68 00:04:07,033 --> 00:04:08,933 its history was mainly Greek. 69 00:04:08,933 --> 00:04:10,733 It was like a Greek city. 70 00:04:10,733 --> 00:04:19,366 ♪♪ 71 00:04:19,366 --> 00:04:21,600 The city gates had been opened, 72 00:04:21,600 --> 00:04:25,166 and the Romans were able to enter peacefully. 73 00:04:25,166 --> 00:04:27,666 But fairly quickly, things got out of hand. 74 00:04:27,666 --> 00:04:31,166 The city was pillaged and set fire to. 75 00:04:34,233 --> 00:04:35,700 A massacre took place, 76 00:04:35,700 --> 00:04:38,533 and the Romans left with all the riches they could find. 77 00:04:43,066 --> 00:04:46,266 What happened was that the city's high temple, 78 00:04:46,266 --> 00:04:48,733 dedicated to Apollo, 79 00:04:48,733 --> 00:04:52,900 "Long-haired Apollo," as he was known at the time, 80 00:04:52,900 --> 00:04:55,133 was where the plundering took place. 81 00:04:55,133 --> 00:04:58,366 And everything considered valuable or prestigious 82 00:04:58,366 --> 00:05:01,266 was taken, 83 00:05:01,266 --> 00:05:04,100 notably the huge statue of Apollo, 84 00:05:04,100 --> 00:05:07,233 which ended up back in Rome. 85 00:05:07,233 --> 00:05:09,333 And so all the Romans were able to see it 86 00:05:09,333 --> 00:05:12,666 at the end of the war when victory had been declared. 87 00:05:17,233 --> 00:05:22,166 Long-haired Apollo was the god of plagues, 88 00:05:22,166 --> 00:05:25,933 the god of healing and medicine, and also the god of archery, 89 00:05:25,933 --> 00:05:28,033 who sent death and disease. 90 00:05:30,733 --> 00:05:32,966 And so, without doubt, 91 00:05:32,966 --> 00:05:34,566 the Romans associated this statue 92 00:05:34,566 --> 00:05:36,400 with the shameful plundering 93 00:05:36,400 --> 00:05:39,833 and pillaging of the city of Seleucia 94 00:05:39,833 --> 00:05:41,566 and with the sort of divine retribution 95 00:05:41,566 --> 00:05:45,600 which befell them afterwards, the epidemic which hit Rome 96 00:05:45,600 --> 00:05:48,966 at more or less the same time as the triumphal victory. 97 00:05:48,966 --> 00:05:54,633 ♪♪ 98 00:05:54,633 --> 00:06:00,133 -Lucius Verus and his army return to Rome victorious in 167 99 00:06:00,133 --> 00:06:02,600 but have unknowingly brought back with them 100 00:06:02,600 --> 00:06:05,733 a dangerous enemy. 101 00:06:05,733 --> 00:06:09,900 The size of the Roman Empire reaches its historic peak. 102 00:06:09,900 --> 00:06:11,766 Estimates put its population 103 00:06:11,766 --> 00:06:15,133 between 50 million and 90 million people, 104 00:06:15,133 --> 00:06:18,800 roughly 20% of the world's population at the time. 105 00:06:21,300 --> 00:06:24,800 But at this moment of triumph, the empire is rocked 106 00:06:24,800 --> 00:06:27,733 by an epidemic of unprecedented strength, 107 00:06:27,733 --> 00:06:30,933 spread by the returning military. 108 00:06:30,933 --> 00:06:35,600 Is Apollo punishing Rome for the destruction of Seleucia? 109 00:06:37,366 --> 00:06:40,466 The Antonine Plague arrives in Rome 110 00:06:40,466 --> 00:06:43,233 in the last years of the Pax Romana, 111 00:06:43,233 --> 00:06:47,100 when the empire is at the height of its power, control, 112 00:06:47,100 --> 00:06:49,233 and population. 113 00:06:49,233 --> 00:06:52,566 The first-known major epidemic to hit the Roman Empire 114 00:06:52,566 --> 00:06:55,333 continues for the next several decades, 115 00:06:55,333 --> 00:06:58,066 and between 5 million and 10 million people 116 00:06:58,066 --> 00:07:01,100 lose their lives. 117 00:07:01,100 --> 00:07:03,633 Galen, an early physician famous 118 00:07:03,633 --> 00:07:09,066 for his medical investigations, recorded the unfolding tragedy. 119 00:07:09,066 --> 00:07:13,700 Véronique Boudon-Millot is an expert on Galen's writings. 120 00:07:16,600 --> 00:07:18,766 -I spent three more years in Rome, 121 00:07:18,766 --> 00:07:20,900 and when the great plague broke out, 122 00:07:20,900 --> 00:07:24,866 I quickly left the city and hurried back to my country. 123 00:07:24,866 --> 00:07:27,766 To my knowledge, there was no 124 00:07:27,766 --> 00:07:30,800 sufficiently powerful medicine to fight this plague, 125 00:07:30,800 --> 00:07:34,166 which spread everywhere before dying out. 126 00:07:37,500 --> 00:07:41,666 Galen left Rome as soon as the epidemic had been declared 127 00:07:41,666 --> 00:07:45,333 and took refuge, so to speak, in his native town, 128 00:07:45,333 --> 00:07:48,533 where he spent two years in relative peace and quiet, 129 00:07:48,533 --> 00:07:52,000 according to what he wrote at the time. 130 00:07:52,000 --> 00:07:55,500 He went about his usual daily life. 131 00:07:55,500 --> 00:07:58,766 And then he received a letter from the joint emperors, 132 00:07:58,766 --> 00:08:02,766 Marcus Aurelius and Lucius Verus, ordering him -- 133 00:08:02,766 --> 00:08:06,733 it was indeed an order -- to join them in Aquileia. 134 00:08:10,433 --> 00:08:14,600 And when he arrived in Aquileia, he found an army camp 135 00:08:14,600 --> 00:08:16,566 where the soldiers were crammed in. 136 00:08:16,566 --> 00:08:18,833 The camp was overcrowded, 137 00:08:18,833 --> 00:08:22,533 and no sooner had he arrived when a terrible epidemic, 138 00:08:22,533 --> 00:08:27,366 stronger than before, broke out and decimated the soldiers. 139 00:08:31,633 --> 00:08:32,833 The two emperors, 140 00:08:32,833 --> 00:08:34,933 Marcus Aurelius and Lucius Verus, 141 00:08:34,933 --> 00:08:36,966 were terrified and left -- 142 00:08:36,966 --> 00:08:39,433 "ran away," in the words of Galen -- 143 00:08:39,433 --> 00:08:40,966 and returned to Rome. 144 00:08:45,100 --> 00:08:49,533 And Galen stayed there alone with a few other army doctors 145 00:08:49,533 --> 00:08:52,033 and had to deal with thousands of casualties, 146 00:08:52,033 --> 00:08:54,833 he tells us, among the soldiers. 147 00:08:59,400 --> 00:09:01,666 Pestilence was like a savage beast, 148 00:09:01,666 --> 00:09:05,333 destroying its victims horribly, devouring them -- 149 00:09:05,333 --> 00:09:08,733 not in small numbers, but whole towns of them. 150 00:09:12,200 --> 00:09:15,500 Most people died not only because of the plague, 151 00:09:15,500 --> 00:09:19,466 but also because it all took place in the heart of winter. 152 00:09:22,000 --> 00:09:24,766 Despite his long experience as a doctor, 153 00:09:24,766 --> 00:09:27,433 having witnessed many things in his career, 154 00:09:27,433 --> 00:09:29,500 he said that the extensive pestilence 155 00:09:29,500 --> 00:09:31,800 was something he'd never seen before, 156 00:09:31,800 --> 00:09:34,533 and he described unheard-of symptoms. 157 00:09:38,466 --> 00:09:41,166 The theory which is most prevalent today 158 00:09:41,166 --> 00:09:44,133 is that it was smallpox, 159 00:09:44,133 --> 00:09:47,700 the very first smallpox epidemic in the Roman world, 160 00:09:47,700 --> 00:09:50,466 with a population who had no immune system 161 00:09:50,466 --> 00:09:55,333 against a disease never before encountered. 162 00:09:55,333 --> 00:09:58,100 The devastation was clearly significant, 163 00:09:58,100 --> 00:10:01,500 but it's still very difficult to put a figure on it. 164 00:10:04,466 --> 00:10:06,133 -Galen notes the devastation 165 00:10:06,133 --> 00:10:10,533 the disease causes at the military camp in Aquileia. 166 00:10:10,533 --> 00:10:13,266 The soldiers are stationed there in preparation for battle 167 00:10:13,266 --> 00:10:17,500 against barbarians from the north and east. 168 00:10:17,500 --> 00:10:20,200 This fighting would go on for years, 169 00:10:20,200 --> 00:10:23,066 as a variety of tribes tested the strength of the Romans 170 00:10:23,066 --> 00:10:25,966 along the Danube and Rhine rivers. 171 00:10:27,600 --> 00:10:33,466 The ongoing conflict takes a toll on the empire. 172 00:10:33,466 --> 00:10:36,500 As the pandemic rages, Rome, 173 00:10:36,500 --> 00:10:39,500 desperate to keep their military fully staffed, 174 00:10:39,500 --> 00:10:43,800 begins recruiting soldiers from across its vast territories, 175 00:10:43,800 --> 00:10:45,500 a decision that may have weakened 176 00:10:45,500 --> 00:10:49,066 the cohesion of the once-mighty army. 177 00:10:49,066 --> 00:10:53,500 Barbarians crossing into Greece, deep in Roman territory, 178 00:10:53,500 --> 00:10:55,033 defeat these soldiers, 179 00:10:55,033 --> 00:10:58,433 one of the empire's first losses. 180 00:10:58,433 --> 00:11:03,800 In August 170, enemy forces attack one of the empire's 181 00:11:03,800 --> 00:11:08,600 most sacred sanctuaries, the Temple of Eleusis, 182 00:11:08,600 --> 00:11:09,833 a place of pilgrimage 183 00:11:09,833 --> 00:11:12,866 famous throughout the Roman world. 184 00:11:12,866 --> 00:11:16,133 This stunning act of violence has repercussions 185 00:11:16,133 --> 00:11:18,066 across Ancient Rome. 186 00:11:20,300 --> 00:11:22,233 -Every year, hundreds of initiates 187 00:11:22,233 --> 00:11:25,300 came in procession through this gate. 188 00:11:25,300 --> 00:11:29,266 The initiates were young, old, men, women, 189 00:11:29,266 --> 00:11:31,266 free citizens, and slaves. 190 00:11:31,266 --> 00:11:35,233 The initiation was open to everybody, on two conditions. 191 00:11:35,233 --> 00:11:36,866 They had to be able to speak Greek 192 00:11:36,866 --> 00:11:39,233 and not have blood on their hands. 193 00:11:40,866 --> 00:11:43,533 If these two conditions of purity were fulfilled, 194 00:11:43,533 --> 00:11:47,433 anyone was entitled to receive the blessings of the goddesses. 195 00:11:49,400 --> 00:11:52,600 -According to Greek mythology, Eleusis is where 196 00:11:52,600 --> 00:11:54,633 the goddess Demeter gave humanity 197 00:11:54,633 --> 00:11:56,533 the gift of agriculture. 198 00:12:00,166 --> 00:12:03,900 A temple was built to honor the site, and every year, 199 00:12:03,900 --> 00:12:07,666 pilgrims arrived to be part of secret religious rites, 200 00:12:07,666 --> 00:12:10,733 known as the Mysteries of Eleusis. 201 00:12:10,733 --> 00:12:12,966 The site's importance for the empire 202 00:12:12,966 --> 00:12:15,100 and the sacred objects within 203 00:12:15,100 --> 00:12:18,666 make the temple an obvious target for the barbarians. 204 00:12:22,433 --> 00:12:24,300 -It was an enormous space, 205 00:12:24,300 --> 00:12:27,800 a jumble of 42 columns 54 meters wide, 206 00:12:27,800 --> 00:12:31,266 20 meters more than the Parthenon. 207 00:12:31,266 --> 00:12:33,133 And in the center of this huge area, 208 00:12:33,133 --> 00:12:35,900 on the side of which were the seats for the initiates, 209 00:12:35,900 --> 00:12:39,633 there as a special chamber, called the Anaktoron. 210 00:12:39,633 --> 00:12:41,800 This was the heart of the sanctuary. 211 00:12:41,800 --> 00:12:43,866 It's still in the same place today, 212 00:12:43,866 --> 00:12:47,000 despite all the changes to the site over the centuries, 213 00:12:47,000 --> 00:12:50,333 and the centerpiece of the ritual. 214 00:12:50,333 --> 00:12:52,133 It's the area where the sacred objects 215 00:12:52,133 --> 00:12:54,833 were shown to the initiates. 216 00:12:56,533 --> 00:12:59,433 And it's here that the initiates discovered something, 217 00:12:59,433 --> 00:13:03,833 which we know very little about, as they were sworn to secrecy. 218 00:13:03,833 --> 00:13:07,066 So we can only surmise as to what happened in this spot 219 00:13:07,066 --> 00:13:09,600 and guess at what the mysteries were. 220 00:13:09,600 --> 00:13:17,333 ♪♪ 221 00:13:17,333 --> 00:13:21,566 -The Costoboci warriors, a tribe from the Southern Balkans, 222 00:13:21,566 --> 00:13:25,133 overrun the shrine, plunder its sanctuary, 223 00:13:25,133 --> 00:13:27,866 and then burn the temple to the ground. 224 00:13:32,633 --> 00:13:35,466 This attack on such an important site 225 00:13:35,466 --> 00:13:38,300 signals Rome's changing fortunes. 226 00:13:38,300 --> 00:13:44,500 ♪♪ 227 00:13:44,500 --> 00:13:47,500 -This is Emperor Marcus Aurelius. 228 00:13:47,500 --> 00:13:50,033 It was his armies who couldn't prevent the Costoboci 229 00:13:50,033 --> 00:13:52,500 getting through 230 00:13:52,500 --> 00:13:55,433 and causing the catastrophic pillage and destruction. 231 00:13:55,433 --> 00:13:56,733 There's a statue of him 232 00:13:56,733 --> 00:13:59,700 because he was the one who had everything rebuilt. 233 00:13:59,700 --> 00:14:06,800 ♪♪ 234 00:14:06,800 --> 00:14:11,633 Between the years 171 and 176, in the Danube region, 235 00:14:11,633 --> 00:14:13,233 there were five years of bitter war 236 00:14:13,233 --> 00:14:17,166 to keep the barbarians at bay and bring about peace. 237 00:14:17,166 --> 00:14:22,566 ♪♪ 238 00:14:22,566 --> 00:14:24,700 From the Greeks' and Romans' perspective, 239 00:14:24,700 --> 00:14:27,633 it would seem that the situation had returned to normal 240 00:14:27,633 --> 00:14:29,900 and that the affront of having been violently plundered 241 00:14:29,900 --> 00:14:31,833 had been forgotten. 242 00:14:31,833 --> 00:14:33,633 But from the barbarians' point of view, 243 00:14:33,633 --> 00:14:36,733 they saw things differently. 244 00:14:36,733 --> 00:14:38,700 They now knew that they could break through. 245 00:14:42,133 --> 00:14:44,200 The warlords could now spot the weaknesses 246 00:14:44,200 --> 00:14:47,500 just across the empire's borders 247 00:14:47,500 --> 00:14:50,266 in the hope of once again seizing valuable booty 248 00:14:50,266 --> 00:14:52,866 and returning triumphant to their own people. 249 00:14:56,300 --> 00:14:59,933 -The unimaginable has happened at Eleusis. 250 00:14:59,933 --> 00:15:04,266 Barbarian tribes in territories surrounding the empire now know 251 00:15:04,266 --> 00:15:09,400 it's possible to defeat the most powerful army in the world. 252 00:15:13,533 --> 00:15:17,166 Despite the military losses, Rome pushes forward 253 00:15:17,166 --> 00:15:21,033 with an immense public-works project. 254 00:15:21,033 --> 00:15:26,066 Emperor Caracalla inaugurates a new complex of thermal baths 255 00:15:26,066 --> 00:15:28,166 in 216 A.D. 256 00:15:30,900 --> 00:15:34,766 -The huge scale and luxury of the Caracalla Baths 257 00:15:34,766 --> 00:15:37,866 demonstrated the prosperity of an empire 258 00:15:37,866 --> 00:15:39,433 that had recovered its strength 259 00:15:39,433 --> 00:15:41,933 and filled its financial coffers. 260 00:15:45,200 --> 00:15:48,066 The 11-hectare baths were the largest in Rome 261 00:15:48,066 --> 00:15:50,566 at the time -- a gigantic construction 262 00:15:50,566 --> 00:15:53,766 built with amazing technical prowess. 263 00:15:56,800 --> 00:16:00,400 Building huge vaulted ceilings and, at the same time, 264 00:16:00,400 --> 00:16:03,933 ensuring that they would resist the heat and humidity 265 00:16:03,933 --> 00:16:05,700 was a masonry nightmare. 266 00:16:08,600 --> 00:16:11,866 -The thermal baths are central to life in Ancient Rome, 267 00:16:11,866 --> 00:16:15,633 serving as important locations for socializing. 268 00:16:15,633 --> 00:16:19,666 Most cities and towns throughout the empire have at least one. 269 00:16:19,666 --> 00:16:23,033 But each bath is also a dangerous place, 270 00:16:23,033 --> 00:16:27,200 where germs are spread and epidemics take hold. 271 00:16:29,233 --> 00:16:31,066 -The emperor created an environment 272 00:16:31,066 --> 00:16:33,166 that was completely controlled, 273 00:16:33,166 --> 00:16:37,400 as the water and air temperatures were regulated. 274 00:16:37,400 --> 00:16:39,966 People came in big groups to meet up, 275 00:16:39,966 --> 00:16:43,966 look after their well-being, and have a healthy lifestyle, 276 00:16:43,966 --> 00:16:46,166 which was important to the Romans. 277 00:16:49,933 --> 00:16:51,666 But from our modern point of view, 278 00:16:51,666 --> 00:16:53,400 this hygiene was deceptive, 279 00:16:53,400 --> 00:16:57,300 because it didn't take into account microorganisms. 280 00:16:57,300 --> 00:16:59,933 Bathing in the same water, which was not chlorinated, 281 00:16:59,933 --> 00:17:03,300 purified, or filtered, 282 00:17:03,300 --> 00:17:05,666 meant that everyone shared the same germs 283 00:17:05,666 --> 00:17:09,600 and the same intestinal parasites. 284 00:17:09,600 --> 00:17:11,100 The baths inevitably 285 00:17:11,100 --> 00:17:14,466 contributed to the spread of diseases in the city. 286 00:17:16,166 --> 00:17:22,600 -In 251 A.D., a second pandemic, likely a hemorrhagic fever, 287 00:17:22,600 --> 00:17:24,900 starts in Alexandria, Egypt, 288 00:17:24,900 --> 00:17:27,966 and sweeps across all of Ancient Rome. 289 00:17:30,166 --> 00:17:32,600 -Just like in the Marcus Aurelius period, 290 00:17:32,600 --> 00:17:34,866 there was a correlation between the disease 291 00:17:34,866 --> 00:17:38,966 and the military problems on the empire's borders. 292 00:17:38,966 --> 00:17:42,566 But, in some ways, from the year 250 onwards, 293 00:17:42,566 --> 00:17:46,366 the danger to the empire was more serious than before. 294 00:17:48,966 --> 00:17:52,066 The enemies really forced their way through. 295 00:17:52,066 --> 00:17:55,333 Pillaging was rife and more extensive, 296 00:17:55,333 --> 00:18:00,300 and the stakes for the army were more serious. 297 00:18:00,300 --> 00:18:03,533 Barbarian invasions led to a greater need for security 298 00:18:03,533 --> 00:18:05,966 in the empire's provinces. 299 00:18:05,966 --> 00:18:10,333 This security emanated from the emperor and his armies. 300 00:18:10,333 --> 00:18:11,833 But since there were simultaneous 301 00:18:11,833 --> 00:18:13,333 and multiple front lines 302 00:18:13,333 --> 00:18:15,633 and one emperor couldn't be omnipresent, 303 00:18:15,633 --> 00:18:18,133 the regions would set about choosing their own. 304 00:18:18,133 --> 00:18:24,133 ♪♪ 305 00:18:24,133 --> 00:18:28,466 It came about that three, four, or more emperors co-existed 306 00:18:28,466 --> 00:18:32,300 for brief periods of time. 307 00:18:32,300 --> 00:18:35,466 So, along with defeat came civil war. 308 00:18:37,900 --> 00:18:40,366 -For the next 30 years, 309 00:18:40,366 --> 00:18:44,300 a succession of emperors and usurpers leads the empire, 310 00:18:44,300 --> 00:18:47,166 most only in power for a few months 311 00:18:47,166 --> 00:18:49,466 and often stationed with their troops 312 00:18:49,466 --> 00:18:51,966 far from the capital. 313 00:18:51,966 --> 00:18:54,133 The empire remains fragmented 314 00:18:54,133 --> 00:18:56,800 until the end of the 3rd century, 315 00:18:56,800 --> 00:18:58,733 when a series of military victories 316 00:18:58,733 --> 00:19:02,400 and reforms unites the empire once again. 317 00:19:02,400 --> 00:19:06,933 But this calm will not last. 318 00:19:06,933 --> 00:19:08,266 -In the 2nd century, 319 00:19:08,266 --> 00:19:11,333 the outer limits of the city of Rome weren't very clear. 320 00:19:14,600 --> 00:19:17,100 It was Aurelian, in the 270s, 321 00:19:17,100 --> 00:19:20,600 who decided to fortify the city by building a wall around it. 322 00:19:20,600 --> 00:19:25,966 ♪♪ 323 00:19:25,966 --> 00:19:29,100 It was a sign of the concern that was weighing on the empire, 324 00:19:29,100 --> 00:19:30,966 because they knew that the barbarians, 325 00:19:30,966 --> 00:19:33,066 as well as the Goths and the Alemanni, 326 00:19:33,066 --> 00:19:34,666 were descending on Italy from the north 327 00:19:34,666 --> 00:19:37,200 time and time again, threatening Milan, 328 00:19:37,200 --> 00:19:40,600 and Rome could be next. 329 00:19:40,600 --> 00:19:44,000 -But the new walls offer only limited protection, 330 00:19:44,000 --> 00:19:47,100 and the city remains an easy target for Germanic 331 00:19:47,100 --> 00:19:50,633 and Eurasian enemies. 332 00:19:50,633 --> 00:19:52,633 Just 30 years later, 333 00:19:52,633 --> 00:19:56,566 the empire's seat of power moves east to Byzantium, 334 00:19:56,566 --> 00:19:57,800 located at the passage 335 00:19:57,800 --> 00:20:01,633 between the Mediterranean and the Black seas. 336 00:20:01,633 --> 00:20:05,500 The new capital is closer to the most dangerous enemies 337 00:20:05,500 --> 00:20:08,800 and easier to defend if invaded. 338 00:20:08,800 --> 00:20:11,466 But the move and the division between the eastern 339 00:20:11,466 --> 00:20:13,866 and western territories of the empire 340 00:20:13,866 --> 00:20:16,833 is another sign that Ancient Rome's strength 341 00:20:16,833 --> 00:20:19,166 is slowly fading. 342 00:20:19,166 --> 00:20:22,033 And with barbarian attacks increasing 343 00:20:22,033 --> 00:20:24,500 and political control fractured, 344 00:20:24,500 --> 00:20:28,833 a new danger threatens the empire -- 345 00:20:28,833 --> 00:20:30,500 climate change. 346 00:20:32,633 --> 00:20:35,200 Today, scientists are finding evidence 347 00:20:35,200 --> 00:20:38,966 in the Czech Republic that shows significant fluctuations 348 00:20:38,966 --> 00:20:44,366 in temperature and rainfall, just when Rome was already weak. 349 00:20:44,366 --> 00:20:49,700 -All plants that live for more than one year 350 00:20:49,700 --> 00:20:51,166 outside the tropics, 351 00:20:51,166 --> 00:20:53,066 so where we have a seasonal cycle 352 00:20:53,066 --> 00:20:56,333 in the climate system, they produce a growth layer. 353 00:20:56,333 --> 00:20:57,966 We call it a ring. 354 00:20:57,966 --> 00:21:01,466 And since most of the plants 355 00:21:01,466 --> 00:21:03,733 that are of interest for us are trees, 356 00:21:03,733 --> 00:21:06,333 we call them tree rings. 357 00:21:06,333 --> 00:21:16,600 ♪♪ 358 00:21:16,600 --> 00:21:19,533 And depending on the growth conditions, 359 00:21:19,533 --> 00:21:23,400 if they are favorable or less favorable, 360 00:21:23,400 --> 00:21:26,366 the ring will be wider or narrower. 361 00:21:27,666 --> 00:21:32,000 So we are basically able to see the fingerprint 362 00:21:32,000 --> 00:21:35,233 of the environment and climate 363 00:21:35,233 --> 00:21:38,566 captured in the tree-ring sequences. 364 00:21:39,966 --> 00:21:45,400 [ Grunting ] So, I expect about 365 00:21:45,400 --> 00:21:51,000 80 to 100 rings 366 00:21:51,000 --> 00:21:53,100 on this oak tree, 367 00:21:53,100 --> 00:21:58,133 so we would basically go back 368 00:21:58,133 --> 00:22:02,033 over most of the 20th century. 369 00:22:02,033 --> 00:22:11,966 ♪♪ 370 00:22:11,966 --> 00:22:16,200 If we take a core sample, we know the outermost ring, 371 00:22:16,200 --> 00:22:17,700 just before bark. 372 00:22:17,700 --> 00:22:21,400 So, the ring that was produced in this summer 373 00:22:21,400 --> 00:22:23,433 has the date 2021, 374 00:22:23,433 --> 00:22:26,200 and then we just count the years back. 375 00:22:29,900 --> 00:22:33,033 -The climate data that scientists collect 376 00:22:33,033 --> 00:22:36,266 from the tree rings can stretch back several centuries, 377 00:22:36,266 --> 00:22:38,266 depending on the age of the tree. 378 00:22:40,366 --> 00:22:44,233 This is the first step in a process scientists will use 379 00:22:44,233 --> 00:22:48,266 to understand the climate of Ancient Rome. 380 00:22:48,266 --> 00:22:51,700 The next step is to look at samples from the oldest wood 381 00:22:51,700 --> 00:22:54,066 they can find. 382 00:22:54,066 --> 00:22:55,700 -Go around this one. 383 00:22:55,700 --> 00:23:02,300 The main timber here in the middle looks good. 384 00:23:05,666 --> 00:23:10,266 This old windmill here is dating approximately 385 00:23:10,266 --> 00:23:13,100 in the beginning of the 18th century, 386 00:23:13,100 --> 00:23:15,666 so it's roughly 200 years old. 387 00:23:15,666 --> 00:23:19,833 By then, the material, the oaks that were used 388 00:23:19,833 --> 00:23:22,100 to build this construction, 389 00:23:22,100 --> 00:23:26,133 are again about 150 to 200 years old. 390 00:23:28,466 --> 00:23:32,033 So that means we are getting back with the tree rings, 391 00:23:32,033 --> 00:23:37,066 with these oak rings, almost 300 to 400 years back in time. 392 00:23:37,066 --> 00:23:44,333 ♪♪ 393 00:23:44,333 --> 00:23:49,533 We need many, many, many rings, rings from many trees. 394 00:23:49,533 --> 00:23:53,333 So that's why we are not only taking one or two cores 395 00:23:53,333 --> 00:23:55,333 from this construction here -- 396 00:23:55,333 --> 00:24:02,066 we will likely extract 20 to 30 cores from individual oaks. 397 00:24:02,066 --> 00:24:09,666 ♪♪ 398 00:24:09,666 --> 00:24:14,100 -Finding wood 2,000 years old requires a visit 399 00:24:14,100 --> 00:24:15,833 to archaeological dig sites, 400 00:24:15,833 --> 00:24:20,466 like this medieval well in the Czech city of Brno. 401 00:24:22,833 --> 00:24:27,933 It dates from the 12th century and contains a rare resource -- 402 00:24:27,933 --> 00:24:30,400 partially fossilized wood, 403 00:24:30,400 --> 00:24:32,833 preserved in the ground for centuries. 404 00:24:32,833 --> 00:24:43,733 ♪♪ 405 00:24:43,733 --> 00:24:46,200 But a new discovery takes the scientists 406 00:24:46,200 --> 00:24:48,600 even further back in time. 407 00:24:48,600 --> 00:24:54,966 ♪♪ 408 00:24:54,966 --> 00:24:59,300 -Gravel pits are a particularly useful source 409 00:24:59,300 --> 00:25:02,133 for such old subfossil material 410 00:25:02,133 --> 00:25:06,633 because the trees must be buried under anaerobic conditions. 411 00:25:06,633 --> 00:25:10,066 So they are somehow in the gravel below the water table. 412 00:25:10,066 --> 00:25:13,000 And you see, we are here in a very flat area. 413 00:25:13,000 --> 00:25:16,166 So, the river was meandering, changing its bed, 414 00:25:16,166 --> 00:25:18,500 over the last centuries and millennia. 415 00:25:18,500 --> 00:25:23,433 The dead trees will fall in the water and they get buried. 416 00:25:27,600 --> 00:25:30,400 We don't know how old the material is. 417 00:25:30,400 --> 00:25:35,666 It can be between 1,000 and 8,000 years before present, 418 00:25:35,666 --> 00:25:38,833 so there is a huge range of possibilities. 419 00:25:38,833 --> 00:25:41,766 And it is so important because this is the material 420 00:25:41,766 --> 00:25:44,800 that really extends our oak chronologies 421 00:25:44,800 --> 00:25:46,633 the furthest back in time. 422 00:25:48,633 --> 00:25:51,633 -For this study, dendrochronologists collect 423 00:25:51,633 --> 00:25:54,100 hundreds of samples of oak trees, 424 00:25:54,100 --> 00:25:58,233 without knowing which historical time period they may be from. 425 00:26:02,066 --> 00:26:04,566 At the Mendel University in Brno, 426 00:26:04,566 --> 00:26:07,533 each of these samples is carefully sanded 427 00:26:07,533 --> 00:26:10,100 so that their rings can be highlighted 428 00:26:10,100 --> 00:26:11,600 and precisely measured. 429 00:26:11,600 --> 00:26:15,600 [ Beeping ] 430 00:26:15,600 --> 00:26:19,466 -Once this is done, we start a process, a technique, 431 00:26:19,466 --> 00:26:21,533 that is called cross-dating. 432 00:26:21,533 --> 00:26:23,800 [ Clicking ] 433 00:26:23,800 --> 00:26:26,800 With enough overlap between the different sources, 434 00:26:26,800 --> 00:26:28,800 from the living material to the relic wood, 435 00:26:28,800 --> 00:26:29,933 the historical timber, 436 00:26:29,933 --> 00:26:32,400 later on, the archeological wood, 437 00:26:32,400 --> 00:26:36,200 and the subfossil one, if we have enough overlap, 438 00:26:36,200 --> 00:26:40,633 if the tree rings match, if they fit together, 439 00:26:40,633 --> 00:26:44,166 we can absolute date all to the historical part. 440 00:26:44,166 --> 00:26:47,900 -These curves show the variations in the width 441 00:26:47,900 --> 00:26:50,500 of the wood rings through time. 442 00:26:50,500 --> 00:26:52,366 Each curve overlaps, 443 00:26:52,366 --> 00:26:54,500 creating a timeline that stretches back 444 00:26:54,500 --> 00:26:56,933 centuries and millennia. 445 00:26:56,933 --> 00:27:00,866 -Once we have all these tree rings together and we can say, 446 00:27:00,866 --> 00:27:07,266 "Ah, this ring is the year 1258, this ring is the year 505," 447 00:27:07,266 --> 00:27:10,933 we take the wood that is absolutely dated, 448 00:27:10,933 --> 00:27:15,000 we cut the material with a small knife -- 449 00:27:15,000 --> 00:27:19,466 have to be very careful that no material from the previous 450 00:27:19,466 --> 00:27:22,366 and the next ring is included in this probe. 451 00:27:22,366 --> 00:27:27,033 So, we talk about thousands and thousands of small probes, 452 00:27:27,033 --> 00:27:29,600 and then the process starts. 453 00:27:29,600 --> 00:27:32,766 We extract the cellulose pure. 454 00:27:32,766 --> 00:27:35,066 We homogenize the cellulose 455 00:27:35,066 --> 00:27:38,566 so that we have a very homogenous mass, 456 00:27:38,566 --> 00:27:44,300 put it in a silver or tin capsule, 457 00:27:44,300 --> 00:27:48,133 and then we have two samples per tree ring. 458 00:27:48,133 --> 00:27:54,066 One we're gonna use for carbon, one for oxygen. 459 00:27:56,666 --> 00:27:59,366 -The carbon and oxygen levels from the samples 460 00:27:59,366 --> 00:28:03,233 tell scientists about historical temperatures and rainfall 461 00:28:03,233 --> 00:28:05,533 that enable them to create an accurate picture 462 00:28:05,533 --> 00:28:07,633 of plant-growth conditions. 463 00:28:09,733 --> 00:28:12,866 -So, if we start in the Roman period -- 464 00:28:12,866 --> 00:28:16,800 so let's say 100 years BC 465 00:28:16,800 --> 00:28:22,700 to about 150, 180 years Common Era -- 466 00:28:22,700 --> 00:28:27,466 we see this was generally dry period. 467 00:28:27,466 --> 00:28:31,800 Dry means, for us, it was likely also warm. 468 00:28:31,800 --> 00:28:34,500 One could say it was favorable. 469 00:28:34,500 --> 00:28:38,933 And it was less fluctuating, so that's an important thing. 470 00:28:38,933 --> 00:28:43,166 Independent of warm or cold, it was more stable. 471 00:28:43,166 --> 00:28:47,900 And then we enter a period around 200 472 00:28:47,900 --> 00:28:50,533 where fluctuations kick in. 473 00:28:50,533 --> 00:28:55,000 In this case, it was getting wetter. 474 00:28:55,000 --> 00:28:58,233 Wetter and potentially also cooler. 475 00:28:58,233 --> 00:29:03,166 And these fluctuations are always unfavorable, 476 00:29:03,166 --> 00:29:09,100 because societies are not able to adapt to them 477 00:29:09,100 --> 00:29:10,766 if they are too fast. 478 00:29:10,766 --> 00:29:12,133 And they are unpredictable. 479 00:29:15,000 --> 00:29:17,266 -The data from the tree rings indicates that 480 00:29:17,266 --> 00:29:21,200 after several centuries of relatively mild temperatures, 481 00:29:21,200 --> 00:29:24,400 a period known as the Roman Climatic Optimum, 482 00:29:24,400 --> 00:29:28,400 the climate in the empire began to cool. 483 00:29:28,400 --> 00:29:31,700 Cyprian, a writer who was also bishop of Carthage 484 00:29:31,700 --> 00:29:35,000 in the 3rd century, described a world where 485 00:29:35,000 --> 00:29:39,800 the sun's rays were less bright and harvests less abundant, 486 00:29:39,800 --> 00:29:43,366 "Only a pale old man on the verge of his grave." 487 00:29:46,966 --> 00:29:51,666 And the empire's problems continue to mount. 488 00:29:51,666 --> 00:29:54,766 With the cooler temperatures, Eurasia's nomadic tribes 489 00:29:54,766 --> 00:29:57,000 move west into Eastern Europe, 490 00:29:57,000 --> 00:30:01,233 in hopes of finding more hospitable land for agriculture. 491 00:30:01,233 --> 00:30:05,266 The Huns, a formidable adversary, 492 00:30:05,266 --> 00:30:10,200 begin attacking the empire's eastern border. 493 00:30:10,200 --> 00:30:12,966 Again, tree rings provide the evidence 494 00:30:12,966 --> 00:30:16,733 for understanding these westward migrations. 495 00:30:16,733 --> 00:30:20,200 -In addition to our research in Central Europe, 496 00:30:20,200 --> 00:30:23,300 we also spent much effort 497 00:30:23,300 --> 00:30:27,566 with our Russian colleagues in Southern Siberia. 498 00:30:27,566 --> 00:30:34,866 ♪♪ 499 00:30:34,866 --> 00:30:38,266 So, this is the great Altai region 500 00:30:38,266 --> 00:30:42,300 at the border between Russia in the north, 501 00:30:42,300 --> 00:30:47,900 Mongolia in the south, China in the southwest, 502 00:30:47,900 --> 00:30:50,100 and Kazakhstan in the west. 503 00:30:50,100 --> 00:31:01,766 ♪♪ 504 00:31:01,766 --> 00:31:04,433 -The present-day Altai Forest starts at an altitude 505 00:31:04,433 --> 00:31:05,700 of 2,400 meters. 506 00:31:08,266 --> 00:31:11,833 We can start from there and go even higher. 507 00:31:11,833 --> 00:31:17,800 ♪♪ 508 00:31:17,800 --> 00:31:21,566 -So, the Altai is particularly important for us to reconstruct 509 00:31:21,566 --> 00:31:26,633 summer temperatures because we find very old living 510 00:31:26,633 --> 00:31:30,933 and relic dead trees at the upper tree line. 511 00:31:30,933 --> 00:31:37,700 ♪♪ 512 00:31:37,700 --> 00:31:40,066 There is a reason why they can't grow higher -- 513 00:31:40,066 --> 00:31:42,400 because it's getting too cold. 514 00:31:42,400 --> 00:31:46,800 So even small changes in summer temperature 515 00:31:46,800 --> 00:31:53,066 will leave a distinct signal in the tree rings. 516 00:31:53,066 --> 00:31:55,933 So the tree rings are almost like a thermometer. 517 00:31:55,933 --> 00:32:07,166 ♪♪ 518 00:32:07,166 --> 00:32:10,200 -The natural conditions in high altitudes are characterized 519 00:32:10,200 --> 00:32:12,233 by extremely low temperatures. 520 00:32:16,500 --> 00:32:19,633 And these temperatures prevent the wood from decomposing. 521 00:32:19,633 --> 00:32:29,800 ♪♪ 522 00:32:29,800 --> 00:32:33,200 Also, very often in mountainous zones, 523 00:32:33,200 --> 00:32:37,166 dead wood doesn't lie on the ground, 524 00:32:37,166 --> 00:32:39,066 but on stone, 525 00:32:39,066 --> 00:32:41,700 which also prevents the destruction of the wood. 526 00:32:41,700 --> 00:32:50,100 ♪♪ 527 00:32:50,100 --> 00:32:52,000 -Once the Russian scientists finish 528 00:32:52,000 --> 00:32:54,000 collecting the wood, they travel to 529 00:32:54,000 --> 00:32:56,900 Novosibirsk State University in Siberia, 530 00:32:56,900 --> 00:32:59,866 where the samples will be dated and measured. 531 00:33:02,333 --> 00:33:05,266 The data is then sent to the University of Cambridge, 532 00:33:05,266 --> 00:33:06,900 in England. 533 00:33:09,466 --> 00:33:10,966 -Very interestingly, 534 00:33:10,966 --> 00:33:14,566 the summer temperature reconstructions from the Altai, 535 00:33:14,566 --> 00:33:18,466 so from Inner Eurasia, which is about 5,000 kilometers 536 00:33:18,466 --> 00:33:22,433 east of the European Alps, are very similar. 537 00:33:22,433 --> 00:33:25,433 [ Beeping ] 538 00:33:25,433 --> 00:33:28,866 ♪♪ 539 00:33:28,866 --> 00:33:35,466 So we have evidence for a more stable, warmer Roman period, 540 00:33:35,466 --> 00:33:38,800 and around the 2nd century A.D., 541 00:33:38,800 --> 00:33:42,666 temperatures become to be more variable, 542 00:33:42,666 --> 00:33:44,933 so there is more fluctuation. 543 00:33:47,866 --> 00:33:52,333 Past agricultural systems were pushed towards their limits, 544 00:33:52,333 --> 00:33:55,066 and nomadic steppe empires -- 545 00:33:55,066 --> 00:33:58,566 those that we know from Inner Eurasia -- 546 00:33:58,566 --> 00:34:01,000 were most likely affected in a way 547 00:34:01,000 --> 00:34:06,300 that they just started to move, to migrate further distances. 548 00:34:06,300 --> 00:34:20,900 ♪♪ 549 00:34:20,900 --> 00:34:24,466 -So, here, we're at an archaeological site 550 00:34:24,466 --> 00:34:27,866 called the Kuraika Cemetery. 551 00:34:29,866 --> 00:34:33,266 It corresponds perfectly with the historical era of the Huns. 552 00:34:33,266 --> 00:34:42,733 ♪♪ 553 00:34:42,733 --> 00:34:45,866 -The Altai has always been a territory which one could call 554 00:34:45,866 --> 00:34:49,600 a crossroads for different populations. 555 00:34:52,966 --> 00:34:55,666 It's a territory where we find traces of nomads 556 00:34:55,666 --> 00:35:00,566 from all eras, 557 00:35:00,566 --> 00:35:02,100 nomads who came one after the other 558 00:35:02,100 --> 00:35:03,666 over several millennia. 559 00:35:05,566 --> 00:35:08,266 [ Shouting ] 560 00:35:10,400 --> 00:35:12,633 When a cold snap happened 561 00:35:12,633 --> 00:35:17,500 and the climate graph indicates a drop in temperatures, 562 00:35:17,500 --> 00:35:20,666 we can see that people migrated 563 00:35:20,666 --> 00:35:24,233 and the Altai territory became depopulated. 564 00:35:27,466 --> 00:35:30,366 In general, people left this region 565 00:35:30,366 --> 00:35:33,166 because farming conditions were deteriorating. 566 00:35:36,333 --> 00:35:39,633 -Once the Huns make it to the eastern edge of the empire, 567 00:35:39,633 --> 00:35:42,300 they discover the region has already been settled 568 00:35:42,300 --> 00:35:45,566 by nomadic tribes from Northern Europe. 569 00:35:45,566 --> 00:35:48,900 Smaller groups, like the Goths, crossed the Danube 570 00:35:48,900 --> 00:35:51,933 and settled in the Balkans and north of Greece, 571 00:35:51,933 --> 00:35:54,800 in present-day Bulgaria. 572 00:35:54,800 --> 00:35:57,566 -They traveled right across the Russian plain, 573 00:35:57,566 --> 00:35:59,433 along the Volga River, 574 00:35:59,433 --> 00:36:03,866 turned south towards Crimea and the Black Sea, 575 00:36:03,866 --> 00:36:07,633 and encountered barbarians well-known to the Romans -- 576 00:36:07,633 --> 00:36:11,500 the Goths and the Sarmatians -- and fought them. 577 00:36:13,866 --> 00:36:16,800 The barbarians neighboring the empire found themselves 578 00:36:16,800 --> 00:36:19,033 caught between the hammer of the Huns 579 00:36:19,033 --> 00:36:23,233 and the anvil of the empire and asked Rome 580 00:36:23,233 --> 00:36:25,900 if they could be integrated into their territory. 581 00:36:29,133 --> 00:36:31,333 The Goths were not at all welcome 582 00:36:31,333 --> 00:36:34,266 once they crossed the Danube. 583 00:36:34,266 --> 00:36:35,666 They found themselves exploited 584 00:36:35,666 --> 00:36:40,033 by the greed of Roman officials in the province. 585 00:36:40,033 --> 00:36:41,733 So they decided to revolt. 586 00:36:45,433 --> 00:36:48,800 -The Goths had hoped Rome would annex their territory 587 00:36:48,800 --> 00:36:52,000 and offer protection from the Huns. 588 00:36:52,000 --> 00:36:55,100 The Romans agree to provide the Goths with security, 589 00:36:55,100 --> 00:36:57,800 but taking advantage of the group's vulnerability, 590 00:36:57,800 --> 00:37:01,933 they also treat them poorly. 591 00:37:01,933 --> 00:37:06,766 In 378 A.D., the Goths revolt. 592 00:37:06,766 --> 00:37:10,200 In Adrianople, northwest of Constantinople, 593 00:37:10,200 --> 00:37:13,800 the Eastern Roman Empire, led by Emperor Valens, 594 00:37:13,800 --> 00:37:19,400 faces off against the Gothic rebels, led by Fritigern. 595 00:37:19,400 --> 00:37:21,866 Believing his forces outnumber the Goths, 596 00:37:21,866 --> 00:37:24,833 Valens goes on the attack... 597 00:37:24,833 --> 00:37:27,666 a decision that proves fatal. 598 00:37:27,666 --> 00:37:29,266 [ Shouting, clanging ] 599 00:37:29,266 --> 00:37:31,200 The Romans find themselves overwhelmed 600 00:37:31,200 --> 00:37:36,366 by the enemy cavalry and reduced to hand-to-hand combat. 601 00:37:36,366 --> 00:37:40,066 It is the greatest defeat in the history of the empire. 602 00:37:44,600 --> 00:37:47,566 Tens of thousands of soldiers are killed, 603 00:37:47,566 --> 00:37:50,900 and the emperor Valens himself dies in battle. 604 00:37:54,200 --> 00:37:57,633 With this major defeat, the Eastern Empire no longer 605 00:37:57,633 --> 00:38:01,866 has the resources to support its other half in the west. 606 00:38:01,866 --> 00:38:05,733 Left vulnerable to attack and more easily reached, 607 00:38:05,733 --> 00:38:09,200 it is only a matter of time until barbarian tribes 608 00:38:09,200 --> 00:38:12,433 conquer the Western Empire. 609 00:38:12,433 --> 00:38:16,033 The Gothic victory reveals Rome has weaknesses 610 00:38:16,033 --> 00:38:17,733 that can be exploited, 611 00:38:17,733 --> 00:38:22,566 bringing its enemies ever closer to the capital city. 612 00:38:22,566 --> 00:38:24,533 No longer the seat of power, 613 00:38:24,533 --> 00:38:28,333 the Eternal City is sacked in 410 A.D., 614 00:38:28,333 --> 00:38:32,000 though battles in the west continue. 615 00:38:32,000 --> 00:38:37,000 Finally, when the Vandals invade North Africa in 429, 616 00:38:37,000 --> 00:38:40,800 the Western Empire disappears altogether. 617 00:38:44,666 --> 00:38:47,466 Well-armed and less exposed to invasion, 618 00:38:47,466 --> 00:38:51,700 the Eastern Empire in Byzantium continues on... 619 00:38:51,700 --> 00:38:54,266 until the beginning of the 6th century, 620 00:38:54,266 --> 00:38:58,266 when Emperor Justinian sees a chance to get revenge 621 00:38:58,266 --> 00:39:01,333 and reconquer lost territories. 622 00:39:02,933 --> 00:39:06,633 But his military strategy fails to consider a force 623 00:39:06,633 --> 00:39:10,200 much stronger than any of the barbaric tribes -- 624 00:39:10,200 --> 00:39:12,533 the climate. 625 00:39:14,633 --> 00:39:17,533 -Let's imagine we're in the year 535. 626 00:39:19,633 --> 00:39:23,800 The eastern provinces of the Roman Empire are doing fine. 627 00:39:23,800 --> 00:39:25,033 They have a new upstart emperor, 628 00:39:25,033 --> 00:39:27,100 who was born in the western provinces, 629 00:39:27,100 --> 00:39:29,033 who speaks Latin as his native tongue, 630 00:39:29,033 --> 00:39:31,700 and has a dream to reconstitute the Roman Empire. 631 00:39:35,966 --> 00:39:40,400 And he targeted as his first goal to reconquer Africa. 632 00:39:42,833 --> 00:39:45,100 Africa fell almost in a matter of months. 633 00:39:45,100 --> 00:39:49,133 The Roman Empire had reconquered the richest breadbasket 634 00:39:49,133 --> 00:39:51,066 of the western half of the Roman Empire 635 00:39:51,066 --> 00:39:53,933 and was poised to now move on Italy. 636 00:39:57,466 --> 00:40:01,800 In 536, they cross from Sicily into the mainland of Italy 637 00:40:01,800 --> 00:40:03,400 and start marching towards Rome. 638 00:40:03,400 --> 00:40:05,166 And they're marching up successfully 639 00:40:05,166 --> 00:40:06,600 in the spring of 536, 640 00:40:06,600 --> 00:40:10,200 when something entirely unexpected happened. 641 00:40:12,700 --> 00:40:15,366 The sun stopped shining for a period of between 642 00:40:15,366 --> 00:40:18,633 12 and 18 months. 643 00:40:18,633 --> 00:40:20,433 A contemporary says that at noon, 644 00:40:20,433 --> 00:40:23,600 the strength of the sun was about like that of the moon. 645 00:40:25,766 --> 00:40:28,133 -What could have made the sun stop shining 646 00:40:28,133 --> 00:40:32,633 in the spring of 536 A.D.? 647 00:40:32,633 --> 00:40:36,000 Was the constant darkness why Justinian failed, 648 00:40:36,000 --> 00:40:39,366 when the whole empire seemed within his reach? 649 00:40:41,033 --> 00:40:43,400 -Do you want to flat out switch to... 650 00:40:43,400 --> 00:40:45,133 -At the University of Maine, 651 00:40:45,133 --> 00:40:48,166 scientists have identified physical evidence 652 00:40:48,166 --> 00:40:50,833 of how the climate was shifting at the same time 653 00:40:50,833 --> 00:40:53,333 Justinian set out to expand the empire. 654 00:40:53,333 --> 00:40:55,566 -...when there's a small iron peak, 655 00:40:55,566 --> 00:40:56,933 but a much higher sulfur peak. 656 00:40:56,933 --> 00:40:59,266 -A unique team of climate specialists 657 00:40:59,266 --> 00:41:01,600 and historians has come together to study 658 00:41:01,600 --> 00:41:03,166 how a natural climate event 659 00:41:03,166 --> 00:41:05,600 could have brought down the Roman Empire. 660 00:41:05,600 --> 00:41:13,500 ♪♪ 661 00:41:13,500 --> 00:41:17,166 This large freezer inside a University of Maine lab 662 00:41:17,166 --> 00:41:19,000 holds an ice core, 663 00:41:19,000 --> 00:41:22,500 which offers insight into what happened in the 6th century. 664 00:41:25,800 --> 00:41:29,633 -This piece is about 60 meters deep. 665 00:41:29,633 --> 00:41:35,033 We keep it in our freezer at temperature minus-25 Celsius. 666 00:41:35,033 --> 00:41:37,166 And right now, 667 00:41:37,166 --> 00:41:41,300 I'm preparing this ice for laser-ablation analysis. 668 00:41:41,300 --> 00:41:46,666 I'm scraping the top part off to remove any contamination 669 00:41:46,666 --> 00:41:49,700 and make the surface flat, as flat as possible. 670 00:41:52,166 --> 00:41:55,133 -This ice core serves as a record of the climate in Europe 671 00:41:55,133 --> 00:41:57,866 for the last 4,000 years. 672 00:42:01,066 --> 00:42:03,733 Scientists retrieved it from a mountain peak 673 00:42:03,733 --> 00:42:06,200 on the border of Switzerland and Italy, 674 00:42:06,200 --> 00:42:10,900 in the heart of what was once the Roman Empire. 675 00:42:10,900 --> 00:42:13,633 -Up until now, most of the great ice-core work 676 00:42:13,633 --> 00:42:16,033 has been done in Antarctica. 677 00:42:16,033 --> 00:42:19,066 There, the technology is perfectly adapted to ice cores 678 00:42:19,066 --> 00:42:21,733 that, as in Greenland, are 3 kilometers long. 679 00:42:21,733 --> 00:42:24,666 In Europe, the situation is completely different. 680 00:42:24,666 --> 00:42:30,800 The ice core, from today to bedrock, is 72 meters. 681 00:42:33,666 --> 00:42:37,066 And the technology was not yet established 682 00:42:37,066 --> 00:42:39,666 which would allow one to see the patterns in ice 683 00:42:39,666 --> 00:42:42,500 that was so heavily compressed. 684 00:42:45,666 --> 00:42:48,366 The Climate Change Institute, under Professor Mayewski, 685 00:42:48,366 --> 00:42:50,866 has perfected a new instrument 686 00:42:50,866 --> 00:42:54,366 which allows one not to measure 100 times in a meter, 687 00:42:54,366 --> 00:42:56,666 but up to 40,000 times. 688 00:42:56,666 --> 00:43:04,533 ♪♪ 689 00:43:04,533 --> 00:43:06,700 -The remarkable thing about this instrument 690 00:43:06,700 --> 00:43:10,533 is that it uses a laser to collect the sample. 691 00:43:10,533 --> 00:43:13,033 And you can actually see it on the screen here. 692 00:43:13,033 --> 00:43:16,033 It almost looks like a worm moving along. 693 00:43:16,033 --> 00:43:19,700 What it's actually doing is, like a tiny jackhammer, 694 00:43:19,700 --> 00:43:24,000 poking away, flaking off chips of the ice. 695 00:43:24,000 --> 00:43:26,333 Once those pieces of ice fly off, 696 00:43:26,333 --> 00:43:28,633 they get incorporated in a gas. 697 00:43:28,633 --> 00:43:33,200 And that gas then takes the sample to this instrument, 698 00:43:33,200 --> 00:43:38,933 which is capable of measuring very, very low concentrations 699 00:43:38,933 --> 00:43:42,300 of things like copper, lead, sodium. 700 00:43:42,300 --> 00:43:45,233 Every single one of these has a different story 701 00:43:45,233 --> 00:43:46,533 about the climate, 702 00:43:46,533 --> 00:43:49,966 about human activity, a variety of things. 703 00:43:54,466 --> 00:43:56,766 -Once they've identified the area of the ice core 704 00:43:56,766 --> 00:43:59,866 that corresponds with the year 536, 705 00:43:59,866 --> 00:44:03,933 scientists find a higher level of sulfur than is normal -- 706 00:44:03,933 --> 00:44:08,300 evidence of a volcanic eruption. 707 00:44:08,300 --> 00:44:11,966 They also find volcanic glass dust in the core sample, 708 00:44:11,966 --> 00:44:16,000 which allows them to locate where the eruption took place -- 709 00:44:16,000 --> 00:44:18,933 Iceland. 710 00:44:18,933 --> 00:44:22,366 But would this volcano have been enough to stop Justinian's 711 00:44:22,366 --> 00:44:24,133 military campaign? 712 00:44:26,333 --> 00:44:28,833 -Determining the magnitude of the eruption 713 00:44:28,833 --> 00:44:34,133 is hard from an ice core, except if you take a look at 714 00:44:34,133 --> 00:44:36,933 the sulfur, the bismuth, and the tin levels, 715 00:44:36,933 --> 00:44:40,633 they're remarkably high for the last 2,000 years. 716 00:44:40,633 --> 00:44:44,800 So that would tell us that the 536 was a very big event. 717 00:44:44,800 --> 00:44:46,833 [ Rumbling, explosion ] 718 00:44:49,400 --> 00:44:51,766 -The eruption threw so much sulfur dioxide 719 00:44:51,766 --> 00:44:55,133 into the atmosphere that, in the years following, 720 00:44:55,133 --> 00:44:58,666 temperatures drop by about 2 degrees -- 721 00:44:58,666 --> 00:45:02,833 one of the coldest periods of the last 2,000 years. 722 00:45:06,666 --> 00:45:08,300 -And so, 536 -- that's the beginning. 723 00:45:08,300 --> 00:45:11,200 Another volcano in 540, another one in 547. 724 00:45:11,200 --> 00:45:13,500 It gets colder and colder and less and less appealing 725 00:45:13,500 --> 00:45:16,133 in terms of crop growth. 726 00:45:16,133 --> 00:45:19,133 And then, in 541, 727 00:45:19,133 --> 00:45:26,000 in the Nile Delta, there explodes a new pathogen. 728 00:45:27,833 --> 00:45:32,266 -In 541 A.D., an epidemic of unprecedented virulence 729 00:45:32,266 --> 00:45:35,433 changes the history of the empire forever. 730 00:45:40,100 --> 00:45:43,033 Today, archaeologists are searching for traces 731 00:45:43,033 --> 00:45:46,033 of this epidemic all across Ancient Rome. 732 00:45:48,400 --> 00:45:52,566 Here on the island of Maguelone, near Montpellier, France, 733 00:45:52,566 --> 00:45:55,233 they suspect the epidemic caused the collapse 734 00:45:55,233 --> 00:45:58,900 of a Mediterranean village. 735 00:45:58,900 --> 00:46:00,300 -This is a magical place. 736 00:46:00,300 --> 00:46:03,000 It's a cathedral built on an island. 737 00:46:05,233 --> 00:46:07,500 It's an island very close to Montpellier, 738 00:46:07,500 --> 00:46:09,133 not far from the mainland, 739 00:46:09,133 --> 00:46:11,566 situated between the marshland and the sea. 740 00:46:13,800 --> 00:46:16,300 It's surprising, because today, we can just drive across, 741 00:46:16,300 --> 00:46:19,600 but in the past, this island was separated from the mainland. 742 00:46:19,600 --> 00:46:25,766 ♪♪ 743 00:46:25,766 --> 00:46:28,600 -We've found Byzantine-style weights and measures, 744 00:46:28,600 --> 00:46:31,300 suggesting that there had been spice merchants here, 745 00:46:31,300 --> 00:46:33,933 trading across the Mediterranean. 746 00:46:33,933 --> 00:46:41,266 ♪♪ 747 00:46:41,266 --> 00:46:43,566 -The first thing you would see on arriving on the island, 748 00:46:43,566 --> 00:46:45,333 probably, were the boats. 749 00:46:45,333 --> 00:46:47,200 There must have been a whole flotilla of seacraft -- 750 00:46:47,200 --> 00:46:48,966 smaller boats and flat-bottomed boats 751 00:46:48,966 --> 00:46:50,666 for navigating the marshes. 752 00:46:50,666 --> 00:47:01,066 ♪♪ 753 00:47:01,066 --> 00:47:04,833 We suspect that they were storage depots, mainly that. 754 00:47:04,833 --> 00:47:08,233 It's likely that there was trade in sheets, wool, cheeses, 755 00:47:08,233 --> 00:47:09,833 and all sorts of goods that don't leave 756 00:47:09,833 --> 00:47:11,833 archaeological traces. 757 00:47:11,833 --> 00:47:20,133 ♪♪ 758 00:47:20,133 --> 00:47:23,500 -In the years 560 to 580, it's noticeable 759 00:47:23,500 --> 00:47:26,366 that the site became depopulated, 760 00:47:26,366 --> 00:47:29,166 and we discovered some rather strange things. 761 00:47:31,333 --> 00:47:32,600 We found corpses, 762 00:47:32,600 --> 00:47:34,933 makeshift burials, which were really just bodies 763 00:47:34,933 --> 00:47:37,600 thrown into the rubble of demolished buildings. 764 00:47:42,266 --> 00:47:46,133 There was an epidemic situation or a war situation. 765 00:47:46,133 --> 00:47:51,133 In any case, the occupying power was in a phase of decline. 766 00:47:51,133 --> 00:47:56,566 ♪♪ 767 00:47:56,566 --> 00:47:58,500 We're trying to shed light onto some of the darker 768 00:47:58,500 --> 00:48:01,966 aspects of this age covering the 5th and 6th centuries. 769 00:48:01,966 --> 00:48:04,833 It's the key period between the Roman and Byzantine worlds 770 00:48:04,833 --> 00:48:06,600 and the emerging medieval world, 771 00:48:06,600 --> 00:48:08,966 with the creation of the Germanic kingdoms. 772 00:48:12,800 --> 00:48:17,933 -So, here, there are two femurs, the thigh bones, 773 00:48:17,933 --> 00:48:19,833 pointing downwards. 774 00:48:24,166 --> 00:48:26,366 The individual doesn't seem to have been buried 775 00:48:26,366 --> 00:48:29,966 horizontally on the site, as would normally happen. 776 00:48:29,966 --> 00:48:33,666 You can see it clearly here -- there are these parts, 777 00:48:33,666 --> 00:48:35,666 which are lying more or less flat, 778 00:48:35,666 --> 00:48:37,966 but when you get to these bones here, 779 00:48:37,966 --> 00:48:39,533 they're pointing down into the earth. 780 00:48:39,533 --> 00:48:42,800 The body might have just been thrown away like that, 781 00:48:42,800 --> 00:48:44,833 like you throw rubbish into a tip. 782 00:48:44,833 --> 00:48:49,000 ♪♪ 783 00:48:49,000 --> 00:48:51,500 -Occasionally, the bodies were thrown away, 784 00:48:51,500 --> 00:48:55,433 literally thrown into a rubbish dump. 785 00:48:55,433 --> 00:48:57,700 Sometimes, they were buried carefully -- 786 00:48:57,700 --> 00:49:01,066 no signs of wealth or caskets or any construction, 787 00:49:01,066 --> 00:49:03,200 but with a certain amount of care. 788 00:49:03,200 --> 00:49:09,700 ♪♪ 789 00:49:09,700 --> 00:49:13,000 -We've also found, for example, a body buried face-down, 790 00:49:13,000 --> 00:49:15,366 which is a terrible punishment for a Christian, 791 00:49:15,366 --> 00:49:18,666 since it signals absolute deprivation from eternal light. 792 00:49:18,666 --> 00:49:25,766 ♪♪ 793 00:49:25,766 --> 00:49:28,366 -Oh, look -- here's a tooth. 794 00:49:31,266 --> 00:49:33,166 -Often, it's teeth 795 00:49:33,166 --> 00:49:36,366 which are the best-preserved parts of ancient corpses. 796 00:49:36,366 --> 00:49:41,600 Sometimes, that's all we find because they fossilize so well. 797 00:49:41,600 --> 00:49:45,433 What's wonderful about this is that they're all there. 798 00:49:45,433 --> 00:49:48,700 And that will enable us, thanks to DNA, 799 00:49:48,700 --> 00:49:52,666 which is so well-preserved in teeth, to study diseases, 800 00:49:52,666 --> 00:49:58,700 in particular the plague, to look for the plague bacillus. 801 00:49:58,700 --> 00:50:04,733 ♪♪ 802 00:50:04,733 --> 00:50:09,733 -Numerous burials in disarray, buildings destroyed, 803 00:50:09,733 --> 00:50:12,566 and the village deserted. 804 00:50:14,400 --> 00:50:17,066 Why was this apparently prosperous town 805 00:50:17,066 --> 00:50:19,866 suddenly abandoned during the 6th century? 806 00:50:19,866 --> 00:50:29,133 ♪♪ 807 00:50:29,133 --> 00:50:31,000 Answers to this question can be found 808 00:50:31,000 --> 00:50:33,266 at the Max Planck Institute in Germany, 809 00:50:33,266 --> 00:50:36,500 where a team specializing in the study of diseases 810 00:50:36,500 --> 00:50:38,866 found in archaeological remains 811 00:50:38,866 --> 00:50:42,600 is now identifying pathogens from Ancient Rome. 812 00:50:42,600 --> 00:50:47,300 Bones are being collected from dig sites all over Europe. 813 00:50:50,866 --> 00:50:53,800 -So, what we usually take as material to start with 814 00:50:53,800 --> 00:50:56,466 are actually teeth from the past, 815 00:50:56,466 --> 00:50:58,266 from a person that has died, 816 00:50:58,266 --> 00:51:01,266 potentially of an ancient infectious disease. 817 00:51:03,600 --> 00:51:04,833 And a tooth is so interesting 818 00:51:04,833 --> 00:51:07,400 because inside the tooth, you have dried blood, 819 00:51:07,400 --> 00:51:08,733 and inside the blood, of course, 820 00:51:08,733 --> 00:51:10,966 the pathogen might have been circulating. 821 00:51:10,966 --> 00:51:12,600 So, how do we get that out? 822 00:51:12,600 --> 00:51:15,100 We have to basically cut the tooth open. 823 00:51:19,933 --> 00:51:23,800 So, we make a cut and then we drill inside that cavity 824 00:51:23,800 --> 00:51:26,300 and remove bone powder -- 825 00:51:26,300 --> 00:51:29,233 little pieces of bone that, on its surface, 826 00:51:29,233 --> 00:51:31,866 might have the DNA of the pathogen bound. 827 00:51:31,866 --> 00:51:43,266 ♪♪ 828 00:51:43,266 --> 00:51:45,800 So, what we then next do is we have to somehow 829 00:51:45,800 --> 00:51:49,333 get the DNA out of that bone powder from the tooth. 830 00:51:49,333 --> 00:51:52,933 So, we do that by dissolving it in a liquid. 831 00:51:52,933 --> 00:51:54,233 So, what you then have is something we call 832 00:51:54,233 --> 00:51:57,100 the DNA extract, which is the extracted DNA 833 00:51:57,100 --> 00:51:58,466 from the ancient bone, 834 00:51:58,466 --> 00:52:04,066 where you then have little pieces of DNA of the person. 835 00:52:04,066 --> 00:52:08,300 You have maybe the pathogen that has killed the person. 836 00:52:08,300 --> 00:52:10,900 But the majority of the DNA that we get 837 00:52:10,900 --> 00:52:13,833 from an ancient skeleton is actually not from the person 838 00:52:13,833 --> 00:52:17,166 and it's not from the pathogen, but it's from the environment, 839 00:52:17,166 --> 00:52:19,166 because the skeleton has been in the ground 840 00:52:19,166 --> 00:52:20,933 for more than 1,000 years, 841 00:52:20,933 --> 00:52:24,233 so it accumulated DNA of many, many micro-organisms. 842 00:52:24,233 --> 00:52:25,900 You really have a soup of DNA, 843 00:52:25,900 --> 00:52:28,166 and just a tiny proportion of that DNA 844 00:52:28,166 --> 00:52:30,600 is actually from the pathogen that you are interested in. 845 00:52:30,600 --> 00:52:36,233 It's maybe something like 0.001% of the DNA 846 00:52:36,233 --> 00:52:38,800 is actually the pathogen DNA that we are interested in. 847 00:52:38,800 --> 00:52:41,233 [ Beeping ] 848 00:52:43,533 --> 00:52:46,133 -In order to find a specific pathogen, 849 00:52:46,133 --> 00:52:50,400 the DNA from the tooth sample is broken into many segments. 850 00:52:54,366 --> 00:52:58,666 The segments are then compared with the DNA of known diseases, 851 00:52:58,666 --> 00:53:02,800 eliminating possibilities like tuberculosis or typhus. 852 00:53:02,800 --> 00:53:07,466 ♪♪ 853 00:53:07,466 --> 00:53:08,900 In the tooth sample, 854 00:53:08,900 --> 00:53:12,533 the scientists identify Yersinia pestis, 855 00:53:12,533 --> 00:53:16,266 the bacteria that causes the Black Plague. 856 00:53:19,033 --> 00:53:21,533 -We have been looking for Yersinia pestis from the time 857 00:53:21,533 --> 00:53:24,233 of the Justinianic Plague, so from the 6th century. 858 00:53:24,233 --> 00:53:26,566 We have actually screened hundreds of human remains 859 00:53:26,566 --> 00:53:29,166 from the time period to see where in Europe 860 00:53:29,166 --> 00:53:31,566 you could find plague during the time of 861 00:53:31,566 --> 00:53:33,000 the Justinianic Plague. 862 00:53:33,000 --> 00:53:34,366 And we were actually quite surprised 863 00:53:34,366 --> 00:53:38,233 because we were finding it in individuals from Iberia, 864 00:53:38,233 --> 00:53:39,766 so from modern-day Spain, 865 00:53:39,766 --> 00:53:41,900 from France, from Germany, from England, 866 00:53:41,900 --> 00:53:45,733 so from large parts of Western Europe. 867 00:53:45,733 --> 00:53:48,766 In about a dozen or so ancient human remains, 868 00:53:48,766 --> 00:53:51,533 we found Yersinia pestis DNA to be preserved, 869 00:53:51,533 --> 00:53:54,033 and we could reconstruct entire genomes 870 00:53:54,033 --> 00:53:56,100 of those ancient plague bacteria. 871 00:53:58,300 --> 00:54:01,400 -Gradually, scientists draw a map of where 872 00:54:01,400 --> 00:54:03,133 they're finding plague, 873 00:54:03,133 --> 00:54:06,733 noting that, based on the succession of waves of illness, 874 00:54:06,733 --> 00:54:11,366 the epidemic lasted roughly a century. 875 00:54:11,366 --> 00:54:16,233 In Constantinople, an estimated 300,000 people died 876 00:54:16,233 --> 00:54:19,666 during the first year of the outbreak. 877 00:54:19,666 --> 00:54:24,200 Despite its vast territory and immense power, 878 00:54:24,200 --> 00:54:25,966 the Roman Empire could not 879 00:54:25,966 --> 00:54:28,500 withstand centuries of mass disease 880 00:54:28,500 --> 00:54:30,066 happening at the same time 881 00:54:30,066 --> 00:54:32,033 that the climate was cooling 882 00:54:32,033 --> 00:54:34,633 and crops were failing. 883 00:54:34,633 --> 00:54:37,633 The process took several hundred years, 884 00:54:37,633 --> 00:54:40,500 but ultimately, Ancient Rome may have 885 00:54:40,500 --> 00:54:43,200 fallen as a result of forces far greater 886 00:54:43,200 --> 00:54:46,300 than military or economic power -- 887 00:54:46,300 --> 00:54:48,033 perhaps a lesson about 888 00:54:48,033 --> 00:54:50,200 the limitations of humanity 889 00:54:50,200 --> 00:54:53,000 in the face of Mother Nature. 890 00:54:53,000 --> 00:54:55,666 ♪♪