The Plague of Justinian, beginning in 541 AD and recurring for two centuries, was caused by the bacterium Yersinia pestis transmitted by fleas on rats. It struck Constantinople during the reign of Emperor Justinian I and is estimated to have killed between 25 and 50 million people across the Byzantine Empire, Persia, and Europe. The plague devastated urban populations, disrupted trade, and contributed to the decline of late antique civilisation, making recovery from the fall of the Western Roman Empire far more difficult.

The historian Procopius, a near-contemporary witness, described the plague in terms that recalled Thucydides, embedding flea-borne catastrophe in the tradition of great historical writing. The massive demographic collapse reduced literary production across the Byzantine world but also intensified the apocalyptic register of religious poetry, hymns, and laments that characterised late antique and early Byzantine verse. The plague confirmed for poets of the era the helplessness of humanity before invisible forces transmitted by the humblest of creatures.