The Intercession of Our Most Holy Lady Theotokos and Ever-Virgin Mary (In Russian Pokrov, Покров) is a feast of the Orthodox Church. For Russian Orthodox it is one of the most important feasts and perhaps the most important after the Twelve Great Feasts. The feast day is October 1.
The origin of the feast of the Pokrov arises from the legend about the miraculous appearance in Constantinople of the Theotokos during the middle of the tenth century. The appearance occurred in the Blachernae Palace church where several of her relics were kept. The relics were her robe, veil, and part of her belt that had been transferred from Palestine during the fifth century.
In early morning of an All-Night Vigil on Sunday October 1 with an over flowing crowd of worshippers St Andrew Fool for Christ, with his disciple St Epiphanius, saw the virgin Mary walking in the air above them glowing with a heavenly light and surrounded by angels and saints. She knelt and prayed for all Christians in the world, imploring the Lord Jesus Christ to accept the prayers of all people and to respond to her intercession. After finishing her prayer of intercession she spread her veil (pokrov) over all the people praying in the church, protecting them from all their enemies.
The Russian Primary Chronicle noted that the intercession of the Theotokos was needed for the protection of the people of Constantinople when a large fleet of the pagan Rus, led by Askole and Dir, was threatening Constantinople. The invading fleet was defeated and the event remembered. Strangely, the feast came to be considered a very important feast by the Slavic Orthodox Churches but not by the Greeks.
A twelfth century Russian chronicle describes the establishment of the intercession as a special feast day honoring the event. Within a few centuries churches began being named in honor of the Protection of the Mother of God.
Among these churches two that are world famous are: in Moscow, the Cathedral of Intercession upon a Moat (In Russian: Храм Покрова "на рву," Cathedral of the Pokrov upon a moat), which is popularly known as the St. Basil’s Cathedral and in Bogolyubovo near Vladimir, the Church of Intercession upon the Nerl River (In Russian: Церковь Покрова на Нерли, Tserkov Pokrova na Nerli).
The Moscow cathedral was built in the mid 1500s by Tsar Ivan IV and the Bogolyubovo church was built in 1165 by Prince Andrew Bogoliusky. In Novgorod, the Monastery of the Intercession of Our Lady (Zverin Monastery) was also built during the twelfth century.