Eunomius (yōnōˈmēəs) [key], c.A.D. 333–A.D. 393?, bishop of Cyzicus (c.361), founder of the Eunomian heresy. He was a disciple and secretary of Aetius whose extreme Arianism he adopted. His followers were called Eunomians or Anomoeans [Gr., = unlike], from their denial of any substantial similarity between God the Father and God the Son. Using Platonic arguments, Eunomius taught that by definition God was unbegotten and that the Son, begotten of the Father, could not therefore be equal to the Father. His learning and sophistication won many admirers. St. Basil the Great refuted him in his doctrinal work Against Eunomius (364). The Eunomians were condemned at the First Council of Constantinople.