Why did the Roman Empire, which dominated Europe and the Mediterranean for five centuries, inexorably weaken until it disappeared? Archaeologists, specialists in ancient pathologies and climate historians are now accumulating clues converging on the same factors: a powerful cooling and pandemics. A disease, whose symptoms described by the Greek physician Galen are reminiscent of those of smallpox, struck Rome in 167, soon devastating its army. At the same time, a... see more