Saint Ilarion (Troitsky; 1886 - 1929) was a Russian Orthodox bishop and theologian, whose most lasting legacy is his writings on Ecclesiology. Finding himself at the center of the Russian Orthodox Church's administration as Patriarch Tikhon's intimate counselor and vicar bishop, the saint quickly met with the ire of the Bolshevik authorities. First arrested in 1919, he was sent into internal exile multiple times, including a stint on Solovki. He ultimately reposed of typhoid fever contracted during his imprisonment and is numbered among the New Martyrs and Confessors of Russia.