Dorotheus bishop of Marcianople, in Mcasia, in the fifth century, was a strong advocate of Nestorianism. He pronounced anathema against all who asserted that Mary was the mother of God. He attended, as a bishop, the Council of Ephesus (opened June 22, 431), which denounced the Nestorians as schismatics; and he was banished to Cappadocia by order of the emperor Theodosius. Four letters of his are preserved in the collection of P. Lupus, entitled Ad Ephesianum Concilium variorum Patrum Epistolae (Louv. 1682, 2 volumes, 4to). — Cave, Hist. Lit. (Genev. 1720), 1:269.