Sabellianism is named after its originator, Sabellius from Cyrenaica. The followers of this heresy believed that God was one substance but three activities. He manifested Himself as the Father in the Old Testament, as the Son in the New Testament, and as the Holy Spirit in Church life.
Dionysius of Alexandria condemned this heresy according to some quotations of Eusebius in the Historia ecclesiastica and by Athanasius. This became an accusation ascribed to every heretic such as Arius and Melitius. Basil the Great said that Sabellianism is a return to Judaism. Sabellianism was condemned in the Council of Constantinople in 381 a.d.