John IV of Constantinople, also known as John the Faster, was a sixth-century prelate who served as the patriarch of Constantinople from 582 until 595. Born in the city to artisan parents, he previously worked as a goldsmith before entering the clergy. He is historically significant for being the first leader to adopt the title of Ecumenical Patriarch. Recognized for his rigorous asceticism and charitable nature, he remains venerated as a saint in several Christian traditions, including the Eastern Orthodox Church.