John of Kronstadt was a prominent 19th-century Eastern Orthodox priest and theologian in the Russian Empire. Born Ivan Ilyich Sergiyev in Sura, he served at St. Andrew's Cathedral in the naval base of Kronstadt. He gained widespread fame for his intense prayer life, his advocacy for frequent Holy Communion, and his extensive charitable activities. Recognized as a wonderworker, he was known for performing mass confessions and providing aid to the impoverished through various social institutions he established.