Monk Isaac and the Dalmatian Monastery of Constantinople/Istanbul (d. AD 383)
Isaac lived as a hermit in a small hut in the wilderness outside of Constantinople. In 378, he left his hermit- age and confronted emperor Valens for supporting the false teaching of Arianism. After continually opposing Valens, Isaac was imprisoned. When Valens died in August 378, the new emperor Theodosius I released Isaac, outlawed Arianism, and reopened the Nicene orthodox churches.
Although Isaac wanted to return to the life of a hermit, a wealthy aristocrat built a Constantinople monastery in his honor. Isaac served as its spiritual leader, and it became the most influential monastery in Constantinople. In 381, Isaac participated in the Ecumenical Church Council held in the Church of Holy Peace (Saint Irene), and assisted in the writing of the final ver- sion of the Nicene Creed. Around 383, Isaac turned the spiritual leadership of the monastery over to his disciple Dalmatius. The monastery later became known as the Dalmatian Monastery. Isaac died in 383.