Russian Orthodox archbishop of Novgorod, Russia, whose leadership in suppressing Judaizing Christian sects occasioned his editing the first Russian translation of the Bible.

Named archbishop in 1485 by the grand prince of Moscow Ivan III (1462–1505), Gennadius initiated a persecution of Christian Judaizers, a movement of zealots stressing the monotheistic element of the Jewish religion and promulgating anti-Trinitarian doctrine. Collaborating with the monastic reformer Joseph of Volokolamsk (Joseph of Volokolamsk, Saint) (Russia), he convoked three synods to counter the heretical sectarians and consciously imitated the model of the 15th-century Spanish Catholic Inquisition against nonconforming Jewish, Arab, and Protestant Christians. When the Judaizers began distributing their own versions of the Old Testament Psalms, Gennadius published the first complete translation of the Old and New Testaments into the Old Church Slavonic language. The translation, made from the Latin Vulgate, was completed with the help of a Croatian Dominican friar, Benjamin.

Because of Moscow's governmental policy of expropriating church property as punishment for Novgorod's separatist tendencies, Gennadius was forced to resign in 1504 and was imprisoned on suspicion of treason.