Antonine+Plague

165-180 AD. Pandemic of smallpox or measles brought back to the Roman Empire by troops returning from campaigns in the Near East. The epidemic claimed the lives of two Roman emperors — Lucius Verus, who died in 169, and his co-regent who ruled until 180, Marcus Aurelius Antoninus. The disease broke out again nine years later, according to the Roman historian Dio Cassius, and caused up to 2,000 deaths a day at Rome, one quarter of those infected. Total deaths have been estimated at five million.Disease killed as much as one-third of the population in some areas, and decimated the Roman army. The weakening of the army by the plague is often thought to have contributed to the invasion of Rome by the Germanic tribes.