Modalism, also called Sabellianism, is the unorthodox belief that God is one person who has revealed himself in three forms or modes in contrast to the Trinitarian doctrine where God is one being eternally existing in three persons. According to Modalism, during the incarnation, Jesus was simply God acting in one mode or role, and the Holy Spirit at Pentecost was God acting in a different mode. Thus, God does not exist as the Father, Son, and Holy Spirit at the same time. Rather, He is one person and has merely manifested himself in these three modes at various times. Modalism thus denies the basic distinctiveness and coexistence of the three persons of the Trinity.