Saint Peter, Bishop of Sebaste, was a brother of Saint Basil the Great and Saint Gregory of Nyssa (January 1 and January 10). His older sister, Saint Macrina (July 19) played a large role in his upbringing.
Saint Basil the Great ordained Saint Peter as presbyter, and later he was made Bishop of Sebaste (in Armenia). Saint Peter was present at the Second Ecumenical Council in the year 381, convened at Constantinople against the heresy of Macedonius.