council · 343 · Serdica
Called by the emperors to reunite the church over Athanasius, Sardica split on arrival: the eastern bishops withdrew to Philippopolis rather than sit with the man they had deposed. The rump under Hosius vindicated Athanasius and passed the canons on appeal to Rome that the papacy would cite for a millennium.
The Council of Serdica, or Synod of Serdica, was a synod convened in 343 at Serdica in the civil diocese of Dacia, by Emperors Constans I, Augustus in the West, and Constantius II, Augustus in the East. It attempted to resolve "the tension between East and West in the Church." "The council was a disaster: the two sides, one from the west and the other from the east, never met as one."
Healing the East–West breach over Athanasius and the Nicene faith.
The western council vindicated Athanasius and wrote canons letting deposed bishops appeal to Rome; the eastern bishops walked out — the breach deepened instead.