Castinus of Byzantium was a Roman senator who became a prominent early Christian leader. After converting to the faith through baptism by Cyrillianus, the bishop of Argyropolis, he dedicated his personal wealth to supporting the impoverished. He served as the bishop of Byzantium from 230 until his death in 237. Although some historical accounts, such as those by Frederick George Holweck, question the existence of bishops in Byzantium during this century, he remains recognized in various traditions.
Life and service
Originally a non-Christian senator from Rome, Castinus underwent a significant religious transformation. Following his conversion, he focused his efforts on church devotion and charitable works. During his leadership in Byzantium, he oversaw a cathedral located near the sea in the area of modern-day Galata. He also commissioned the construction of an early church dedicated to Saint Euphemia.
Veneration
He is commemorated as a saint within the Catholic and Orthodox traditions. His memory is honored annually on 25 January. Some historical writings, including those by Nicephorus Callistus, refer to him by the name Constantine.