Urchristentum
Both Successionists and Restorationists among Oneness Pentecostals assert that the early apostolic church believed in the Oneness and Jesus name baptism doctrines. Oneness theologian David K. Bernard claims to trace Oneness adherents back to the first converted Jews of the Apostolic Age. He asserts that there is no evidence of these converts having any difficulty comprehending the Christian Church's teachings and integrating them with their existing strict Judaistic monotheistic beliefs. In the post-Apostolic Age, Bernard claims that Hermas, Clement of Rome, Polycarp, Polycrates, Ignatius (who lived between 90 and 140 A.D.), and Irenaeus (who died about 200 A.D.) were either Oneness, modalist, or at most a follower of an "economic Trinity," that is, a temporary Trinity and not an eternal one.