Isidore of Chios was a 3rd-century Egyptian soldier serving in the Roman navy. While stationed on the Aegean island of Chios, he declared his Christian faith to his fleet commander. Refusing to renounce his beliefs or worship state deities, he faced execution during the persecutions led by Emperor Decius. He was beheaded and his remains were discarded in a cistern, an event that occurred around 251.