Solovetsky Monastery () was the greatest citadel of Christianity in the Russian North before being turned into a special Soviet prison and labor camp (1926–1939), which served as a prototype for the Gulag system. Situated on the Solovetsky Islands in the White Sea, the monastery braved many changes of fortune and military sieges. Its most important structures date from the 16th century, when Filip Kolychev was its hegumen.