Which pandemic first struck the Byzantine Empire in 541?

The pandemic that first struck the Byzantine Empire in 541 was the Plague of Justinian. It began in Roman Egypt, probably reaching the port of Pelusium before spreading through the Mediterranean world, including Constantinople, the empire’s capital.

The outbreak is named after Emperor Justinian I, whose reign coincided with its first major wave. The Byzantine historian Procopius described the epidemic and reported that Justinian himself became ill but survived. The disease was caused by Yersinia pestis, the same bacterium associated with the later Black Death, although the two outbreaks were separated by roughly eight centuries.

The plague disrupted farming, taxation, trade, military recruitment, and Justinian’s ambitious campaigns to reconquer former Western Roman territories. Its death toll remains disputed because contemporary reports used dramatic figures and modern evidence is incomplete. The first wave lasted roughly from 541 to 549, while recurring outbreaks continued for centuries.

A common mix-up is calling it the Black Death. The Black Death was the major second plague pandemic of the 14th century; Justinian’s outbreak is generally regarded as the first major pandemic of plague.