Sabellianism, Christian heresy that was a more developed and less naive form of Modalistic Monarchianism (see Monarchianism); it was propounded by Sabellius (fl. c. 217–c. 220), who was possibly a presbyter in Rome. Little is actually known of his life because the most detailed information about him was contained in the prejudiced reports of his contemporary, Hippolytus, an anti-Monarchian Roman theologian. In Rome there was an active struggle between the Monarchians, or Modalists, and those who affirmed permanent distinctions (“Persons”) within the Godhead. The Monarchians, in their concern for the divine monarchy (the absolute unity and indivisibility of God), denied that such distinctions were ultimate or permanent. Sabellius evidently taught that the Godhead is a monad, expressing itself in three operations: as Father, in creation; as Son, in redemption; and as Holy Spirit, in sanctification. Pope Calixtus was at first inclined to be sympathetic to Sabellius’ teaching but later condemned it and excommunicated Sabellius.
The heresy broke out again 30 years later in Libya and was opposed by Dionysius of Alexandria. In the 4th century, Arius accused his bishop of Sabellianism, and throughout the Arian controversy this charge was levelled at the supporters of Nicene orthodoxy (those who accepted the doctrine of the Trinity set forth in the Nicene Creed), whose emphasis on the unity of substance of Father and Son was interpreted by Arians to mean that the orthodox denied any personal distinctions within the Godhead. About 375 the heresy was renewed at Neocaesarea and was attacked by Basil the Great. In Spain Priscillian seems to have enunciated a doctrine of the divine unity in Sabellian terms.
At the time of the Reformation, Sabellianism was reformulated by Michael Servetus, a Spanish theologian and physician, to the effect that Christ and the Holy Spirit are merely representative forms of the one Godhead, the Father. In the 18th century, Emanuel Swedenborg, a Swedish mystical philosopher and scientist, also taught this doctrine, as did his disciples, who founded the New Church.