John IV of Constantinople
John IV (died September 2, 595), also known as John Nesteutes (Greek: Ιωάννης Νηστευτής, Ioannes the Faster), was the 33rd bishop or Patriarch of Constantinople (April 11, 582 – 595). He was the first to assume the title Ecumenical Patriarch. He is regarded as a saint by the Eastern Orthodox Church which holds a feast on September 2.