This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Almost nothing reliable survives from Sabellius himself, and what is known of his teaching comes almost entirely through opponents, which is itself a caution about how confidently the position can be described. The core claim attributed to him is straightforward: the one God appears under three names, Father in creation, Son in redemption, Spirit in sanctification, as a single actor takes different roles, rather than existing eternally as three distinct persons.
Tertullian, writing in Latin North Africa, gave the objection its lasting name, calling the consequence patripassianism, the Father suffering, since if Father and Son are simply one person under two names, then the Father himself must have hung on the cross, a conclusion Tertullian found both absurd and doctrinally intolerable. Pope Callistus the First excommunicated Sabellius at Rome around the year 220, and decades later, around 262, Dionysius of Alexandria wrote against a version of the same teaching circulating in Libya, provoking a sharp exchange of letters with Dionysius of Rome over how strongly to state the distinction between Father and Son without tipping into a different error, treating them as two separate gods.
No ecumenical council ever took the position up by name, since regional censure had already marginalized it well before Nicaea met in 325. But the creed that council produced, confessing the Son as a distinct person, of one substance with the Father, excludes modalism as completely as it excludes the opposite error of Arianism, without needing to say so directly.