The Martyrs Urban, Theodore, Medimnus and seventy-nine companions suffered at Nicomedia during the reign of the Arian emperor Valentus (Valens) (364-378 or 379). The Orthodox bishop Evagrius was banished from the Church of Constantinople, and Christians not wishing to accept the Arian heresy were locked up in prison and subjected to various outrages.

Driven to the point of despair, the Orthodox Christians decided to ask for protection from the emperor and they sent 80 chosen men of religious rank, headed by Sts Urban, Theodore and Medimnus.

Hearing their justified complaints, the emperor flew into a rage, but he know how to hide his wrath. He quietly summoned the eparch Modestus and ordered him to put the delegates to death. Modestus put them upon a ship, telling them that they all would be sent to prison. Instead, he ordered the ship's officers to burn the ship on the open sea. The ship was set afire and for a while, it floated upon the sea. Finally, reaching a place called Dakizis, the ship burned up with all the holy martyrs on board.