Saint Theosebia the Deaconess was the sister of Saints Basil the Great, Gregory of Nyssa, and Peter, Bishop of Sebaste. She was a virgin and served the Holy Church as a deaconess, caring for the sick, distributing food to vagrants, raising orphans and preparing women for holy Baptism.
When her brother, Saint Gregory of Nyssa, was in exile for three years, Saint Theosebia was with him and she shared in all the tribulations of a life of wandering. Saint Theosebia died in 385, and Saint Gregory the Theologian praised her in a eulogy.