Photinus (Greek: Φωτεινός; died 376) was a Christian bishop of Sirmium in Pannonia Secunda (today the town Sremska Mitrovica in Serbia), best known for denying the incarnation of Christ, thus being considered a heresiarch by both the Catholic and Orthodox Churches. His name became synonymous in later literature for someone asserting that Christ was not God. His teachings are mentioned by various ancient authors, like Ambrosiaster (Pseudo-Ambrose), Hilary of Poitiers, Socrates Scholasticus, Sozomen, Ambrose of Milan, Augustine of Hippo, John Cassian, Sulpicius Severus, Jerome, Vigilius of Thapsus and many others. None of his writings are extant; his views must be reconstructed through his critics. Photinus grew up in Ancyra in Galatia, where he was a student and later a deacon of bishop Marcellus. Marcellus, in later life a staunch opponent of Arianism, was excommunicated and deposed in 336 but rehabilitated by the Synod of Serdica in 343, which also made Photinus bishop of Sirmium. In 344, the Synod of Antioch deposed Marcellus and drew up the Macrostich, a creed which listed their beliefs and objections to Marcellus's doctrines (among others). R. P. C. Hanson (1973) described Photinus' Christology as consistent with the early teachings of Marcellus between 340 and 350. At the time Photinus voiced his own theological system, according to which Jesus was not divine and the Logos did not exist before the conception of Jesus. For Photinus the Logos was simply a mode of manifestation of the Father, hence he denied the pre-existence of Christ and saw theophanies in the Old Testament as of the father, and the image of the "Son of God" (actually, Son of man) in front of (and distinct from) the Ancient of Days as prediction only. Photinus's apprehension of God as Father, and his teachings about the nature of Jesus Christ are maybe more complex than has been thought. The church historian Socrates Scholasticus identifies Photinus' beliefs with those of Sabellius, Paul of Samosata and Marcellus.