Justinian Plague: First Major Recorded Pandemic

The Justinian Plague erupted across the Byzantine Empire beginning in 541 CE at Pelusium, Egypt. Caused by the bacterium Yersinia pestis, it devastated Constantinople and spread throughout Europe, North Africa, and parts of Asia. The pandemic killed an estimated 25-50 million people, representing 15-40% of affected populations. This demographic catastrophe weakened the Byzantine Empire during Emperor Justinian's attempts to reconquer western territories, significantly altering the political landscape of the early medieval world. Archaeological evidence confirms the plague's wide geographic spread, including regions not mentioned in historical texts.