John of Kronstadt or John Iliytch Sergieff (pre-reform Russian: Іоаннъ Кронштадтскій; post-reform Russian: Иоа́нн Кроншта́дтский; 31 October [O.S. 19 October] 1829 – 2 January 1909 [O.S. 20 December 1908]) was a Russian Orthodox archpriest and a member of the Most Holy Synod of the Russian Orthodox Church. He was known for his mass confessions, numerous miracles, and charitable work, as well as his monarchistic, chauvinistic and anti-communist views.
John is a saint of the Eastern Orthodox Church and is known with the epithet "Righteous".