Кирилло-Белозерский монастырь
In the 13th century, the area belonged to the Principality of Beloozero, and in the 14th century, together with the rest of the principality, it became a part of the Grand Duchy of Moscow. In 1397, St. Cyril of Beloozero, a monk and a disciple of St. Sergius of Radonezh, founded the Kirillo-Belozersky Monastery on the shore of Lake Siverskoye. The town of Kirillov eventually developed as the "posad" of the monastery. In 1398, St. Therapont of Beloozero, who arrived with Cyril, moved to a separate location, which later became the Ferapontov Monastery. Both monasteries were subordinate to Archbishops of Rostov. In the 15th and the 16th centuries, Kirillo-Belozersky Monastery developed into one of the most influential monasteries in Russia. It also helped that the Sheksna River was one of the most heavily used waterways connecting central and northern Russia. At some point, the monastery was the second biggest landowner after the Trinity Lavra of St. Sergius. Vasily III, the Grand Prince of Moscow, and Ivan the Terrible, the Tsar, visited the monastery on several occasions. In the end of the 15th century, Nil Sorsky, a former monk of the monastery and a leader of non-possessors movement in the Russian Orthodox Church, founded the Nilo-Sorsky Monastery northwest of Kirillov.