Upon leaving prison, he joined the monastery of St. Joseph of Volokolamsk, where he was [[tonsure|tonsured]] with the name '''Gurias'''. In 1543, he became the abbot ([[Igumen|hegumenos]]) of the monastery.After serving in this capacity until 1552, he left the position and lived for 2 years as a simple monk.<ref name="stjohndc"/>He became abbot of the Selizharov Monastery in Tver<ref name="epar">http://eng.kazan.eparhia.ru/bishops/bishops/ ''Kazan bishops.''] Moscow Patriarchate of the Russian Orthodox Church</ref>. In July, 1555, he was chosen to be the first [[bishop]] of the new [[Diocese of Kazan]].