Monk Dalmatius and Dalmatian Monastery of Constantinople/Istanbul (d. AD 446)
Dalmatius served in the army of emperor Theodosius II. Around 381, he left the army and with his son Faustus joined the Constantinople monastery of Isaac, where they lived consecrated spiritual lives. At the end of his life, Isaac entrusted the monastery’s spiritual leadership to Dalmatius, and it became known as the Dalmatian Monastery. Along with most of Constantinople’s monks, Dalmatius opposed the teaching of Nestorius.
Although Dalmatius had never left the monastery in forty years, he led a large number of monks to Theodosius II’s palace to protest his support of Nestorius. Dalmatius participated in the Ephesus Ecumenical Church Council in 431 that condemned Nestorius’ teaching. When Dalmatius died around 446, at the age of ninety, his son Faustus became the monastery’s new spiritual leader.