October 1 on the Julian calendar, October 14 on the Gregorian. The Intercession of the Theotokos, or the Protection of Our Most Holy Lady Theotokos and Ever-Virgin Mary, is a Christian feast of the Mother of God celebrated in the Eastern Orthodox and Byzantine Catholic Churches on October 14 or October 1. The feast celebrates the protection afforded the faithful through the intercessions of the Theotokos (lit. Mother of God, one Eastern title of the Virgin Mary). The feast is commemorated in Eastern Orthodoxy as a whole, but by no means as fervently as it is in Russia, Belarus, and Ukraine. In the Slavic Orthodox Churches it is celebrated as the most important solemnity besides the Twelve Great Feasts and Pascha. In Ukraine, it has a special meaning through its connection to the spirituality of the Ukrainian Cossacks and, accordingly and more recently, to Defenders of Ukraine Day. Wiki link Dates computed on the Julian calendar. Text: Wikipedia (CC BY-SA).