Eastern Greek speaking Christians and western Latin speakers had already begun to diverge somewhat on practice and beliefs. A key point was the exact nature of Christ’s divinity. Was he truly God the Father’s equal, or merely First among His creations? The language barrier complicated the dispute. One point they found they could agree on was hatred of their Jewish neighbors. In fact, 4th century Christians imagined they were persecuted by Jews for their belief in a Messiah who had already come.
“The fact that any active persecution of Christians by Jews was a thing of the past by the second century made little impression on the pious mind. Jewish responsibility for the Passion of Christ was the fact uppermost in the minds of ecclesiastical writers. When contemporary Jews or contemporary events in Jewish history were described, the preoccupation of the church fathers with the ancient day of sorrow made them merge the present with the past in wild anachronisms and attach the opprobrium connected with the Jews of Christ’s time to their fourth century descendants.”
– The Persecution of Jews in the Roman Empire (300-428), James Everett Seaver, University of Kansas Publications, Humanistic Studies #30 (1952)
At the First Council of Nicea in 325, Constantine presided over bishops from his vast empire as the established the beginnings of church orthodoxy, resplendent in robes of purple and gold. Contemporary Christians had objected to the Jewish lunar calendar and how it did not align with a solar calendar for some time. A unified Julian solar calendar was chosen, further divorcing Roman Christians from their Jewish contemporaries, one that moved Easter to the following Sunday from the Jewish Pesach (Passover) Festival.
By this quarter point in the fourth century, the collective charge of deicide – murder of a god – was clearly established against the Jewish people and widely held by the Christian bishops of Rome. The emperor himself did not vote in the religious council modeled after the Senate, but observed the proceedings with royal records keepers. After the Council, Constantine wrote a letter to the bishops who had not been able to attend to inform them of the decisions of their peers. Deicide and antisemitism come through strongly in his discussion of Easter.
“[I]t seemed very unworthy for us to keep this most sacred feast following the custom of the Jews, a people who have soiled their hands in a most terrible outrage, and have thus polluted their souls, and are now deservedly blind.”
Life of Constantine, Book III