He visited the holy places in Moscow, but he did not find it suitable in spirit and so set out to the Novgorod region. The destiny of the future ascetic was decided by an encounter with Saint Alexander of Svir (August 30). With his blessing, Gregory went to the Vologda forest to Saint Cornelius of Komel (May 19), and was tonsured by him with the name Gennadius. Together with Saint Cornelius, Gennadius moved on to the Kostroma forest. Here, on the shores of Lake Sura, in about the year 1529, there emerged the monastery of the Transfiguration of the Lord, afterwards called “the Gennadiev monastery”. Having become igumen, Saint Gennadius did not slacken his monastic efforts, and together with the brethren he went out to the monastery tasks: he chopped wood, carried firewood, made candles and baked prosphora. He also wore heavy chains. One of his favorite tasks was the painting of icons, with which he adorned his new monastery.
For his holy life Saint Gennadius received from the Lord the gift of clairvoyance and wonderworking. Journeying to Moscow on monastic affairs, at the house of the nobleman Roman Zakharin, the saint predicted to his daughter Anastasia that she would become Tsaritsa. Indeed, Tsar Ivan the Terrible chose her as his wife.
The Life of Saint Gennadius was written by his disciple, Iguman Alexis, between the years 1584-1587. In it was inserted his spiritual testament, dictated by Saint Gennadius himself. In it he commands the monks to observe the monastery Rule, to toil constantly, to be at peace with everyone, and to preserve the books collected at the monastery, while striving to understand their meaning. He said, “Strive towards the light, and shun the darkness.”
Saint Gennadius died on January 23, 1565, and was glorified by the Church on August 19, 1646.