The Christian theologian and leader Marcion (active mid-2nd century) promulgated views that were condemned as heterodoxy.

Marcion came from the Black Sea seaport town of Sinope on what is now the northern shore of Turkey. According to the writer Hippolytus, his father was the bishop of Sinope, so Marcion may well have been raised as a Christian. Once grown, Marcion entered the ministry and, toward the middle of the 2nd century, moved to Rome. There he gathered followers and in time began publically promulgating his theological views to the Roman Church at large. To his surprise, these views were not received sympathetically, and at the first known Roman synod, Marcion was excommunicated (144). Subsequently he became the founder of the rival Marcionite Church, which, in its ecclesiastical life, liturgy, and sacraments, paralleled the Christian Church. Marcion's rival church grew with considerable success, and Marcionite communities were found throughout...