Saint of Slavic origin who lived in Constantinople, known as a 'Holy Fool' (Yurodivy) — a saint who feigned madness for spiritual purposes. He is most famous for his vision of the Protection (Pokrov) of the Mother of God at the Church of Blachernae, where he saw the Blessed Virgin extending her veil over the faithful. This vision became the basis for one of the most important Orthodox feast days (Pokrov, October 1st). He also prophesied about the fall of Constantinople and the coming of the Antichrist.