Monastic Life and Foundation
According to tradition, Sebastian felt a disposition toward the ascetic life even as a teenager and entered one of the many monasteries then active in the region. He served in various monastic roles and was ordained as both hierodeacon and hieromonk.
Rather than remaining within the walls of an established house, Sebastian withdrew into the dense forests of the Poshekhonye region, along the River Sokhota, some 90 versts from the city of Romanov (now Tutaev) in the Yaroslav district. There he built a temple dedicated to the Transfiguration of the Lord.
His solitary efforts drew other monks to him, and a monastic community formed under his guidance. Known as the Sokhota Monastery, it later came to be called the Poshekhonye Monastery. The monks supported themselves by cultivating the soil, living from the work of their own hands.
Biographical details about Sebastian remain scarce; practically no information survives concerning his childhood and early life.