The Holy Prince Theodore of Smolensk and Yaroslavl, nicknamed Black, was born in the terrible time for Russia of the Mongol invasion, about 1237-1239, and was baptized in the name of the Holy Great Martyr Theodore Stratilates, especially revered by the Russian princes-warriors.
Through military exploits, God was destined to be glorified in the Russian land and the holy Prince Theodore. In 1239, when, through the prayers of the Most Holy Theotokos, the holy warrior-martyr Mercury delivered Smolensk from Batu's captivity, the youth Theodore was not in the city: he was taken away and hid for the duration of the war in a safe place. The following year, in 1240, his father, Prince Rostislav, great-grandson of the noble Prince Rostislav of Smolensk and Kiev, died. The elder brothers, heirs, divided the lands of their father among themselves, allocating the little Mozhaisk to the youngest - the lad Theodore. Here he spent his childhood, here he studied the Holy Scriptures, church service and martial arts.
In 1260, the holy Prince Theodore married Maria Vasilievna, daughter of the holy noble Prince Vasily of Yaroslavl, and became Prince of Yaroslavl. Their son Michael was born, but soon Saint Theodore became a widower. He spent a lot of time in military labors and campaigns, his son was brought up by his mother-in-law, Princess Xenia.