In classical Christian use, the term "orthodox" refers to the set of doctrines which were believed by the early Christians. A series of ecumenical councils were held over a period of several centuries to try to formalize these doctrines. The most significant of these early decisions was that between the homoousian doctrine of Athanasius and Eustathius (which became Trinitarianism) and the Heteroousian doctrine of Arius and Eusebius ("Arianism"). The homoousian doctrine, which defined Jesus as both God and man with the canons of the 431 Council of Ephesus, won out in the Church and was referred to as "orthodoxy" in most Christian contexts, since this was the viewpoint of previous Christian Church Fathers and was reaffirmed at these councils. (The minority of nontrinitarian Christians object to this terminology.)