Founded in 1397 by Cyril Bielozerski, a disciple of the highly venerated Sergius of Radonezh, St. Cyril of the White Lake was one of the largest and most influential monasteries in Russia. Enjoying the support of princes and tsars, it prospered until the 18C, when it was destroyed by a fire. Set on the lakeside, it houses two monasteries (Dormition and Ivanov) and eleven churches behind its thick fortifications, built in the 17C as protection against the Swedes.