Saint Isaac the Confessor, also Isaacius or Isaakios (Greek: Ἰσαάκιος or Ἰσάκιος; died May 30, 383 AD), founder of the Dalmatian Monastery in Constantinople, was a Christian monk who is honored as a saint and confessor. He is sometimes referred to as Isaac the Dalmatian, not because he came from Dalmatia, but because of the monastery which he founded.