Original: Sabellianism has been rejected by the majority of Christian churches in favor of Trinitarianism, which was eventually defined as three distinct, co-equal, co-eternal persons by the Athanasian Creed late in the fourth century.
Simplified: Sabellianism has been rejected by the majority of Christian churches in favor of Trinitarianism. This was done through the Athanasian Creed, which says that God is three distinct persons.