Eusebius of Nicomedia

Eusebius of Nicomedia (/juːˈsiːbiəs/; Ancient Greek: Εὐσέβιος; died 341) was an Arian priest who baptised Constantine the Great on his deathbed in 337. A fifth-century legend evolved that Pope Sylvester I was the one to baptise Constantine, but this is dismissed by scholars as a forgery "to amend the historical memory of the Arian baptism that the emperor received at the end of his life, and instead to attribute an unequivocally orthodox baptism to him". He was a bishop of Berytus (modern-day Beirut) in Phoenicia. He was later made the bishop of Nicomedia, where the Imperial court resided. He lived finally in Constantinople from 338 up to his death.