Castinus I (? – 237) was reputedly the

Bishop of Byzantium The ecumenical patriarch ( el, Οἰκουμενικός Πατριάρχης, translit=Oikoumenikós Patriárchēs) is the archbishop of Constantinople (Istanbul), New Rome and ''primus inter pares'' (first among equals) among the heads of the ...

between 230 and 237. In some catalogues he appears as Constantine. He was a senator from

Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus (legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...

, who initially was not a Christian. He converted to

Christianity Christianity is an Abrahamic monotheistic religion based on the life and teachings of Jesus of Nazareth. It is the world's largest and most widespread religion with roughly 2.38 billion followers representing one-third of the global pop ...

, being baptised by the

bishop A bishop is an ordained clergy member who is entrusted with a position of authority and oversight in a religious institution. In Christianity, bishops are normally responsible for the governance of dioceses. The role or office of bishop is ca ...

of Argyropolis, Cyrillianus. From then on he gave his fortune to the poor and was devoted to the Church. He was bishop of

Byzantium Byzantium () or Byzantion ( grc, Βυζάντιον) was an ancient Greek city in classical antiquity that became known as Constantinople in late antiquity and Istanbul today. The Greek name ''Byzantion'' and its Latinization ''Byzantium'' cont ...

from 230 to 237. Until his tenure, the cathedral was near the sea in the area of present

Galata Galata is the former name of the Karaköy neighbourhood in Istanbul, which is located at the northern shore of the Golden Horn. The district is connected to the historic Fatih district by several bridges that cross the Golden Horn, most notabl ...

. He built one of the oldest churches in Byzantium to honour

Saint Euphemia Euphemia ( el, Εὐφημία; "well-spoken f), known as the All-praised in the Eastern Orthodox Church, was a virgin, who was martyred for her faith at Chalcedon in 303 AD. According to tradition, Euphemia was arrested for refusing to offer ...

. Nicephorus Callistus refers to him in his works as Constantine. His memory is revered on January 25. Church historian

Frederick George Holweck Frederick George Holweck (born Friedrich Georg Holweck; 29 December 1856 – 15 February 1927) was a German-American Catholic parish priest and scholar, hagiographer and church historian. Monsignor Holweck contributed some articles to the ''Catho ...

says that there were no bishops at Byzantium in the third century.Holweck, Frederick George. ''A Biographical Dictionary of the Saints: With a General Introduction on Hagiology''
United Kingdom, B. Herder Book Company, 1924. p. 194

References

Sources

The Ecumenical Patriarchate of Constantinople
{{Authority control 3rd-century Romans 3rd-century Byzantine bishops Bishops of Byzantium 3rd-century Christian saints