Feast of Orthodoxy

Icon of the Triumph of Orthodoxy illustrating the "Triumph of Orthodoxy" under the Byzantine empress Theodora and her son Michael III over iconoclasm in 843. Late 14th to early 15th century icon (National Icon Collection 18, British Museum).

The Feast of Orthodoxy (or Sunday of Orthodoxy or Triumph of Orthodoxy) is celebrated on the first Sunday of Great Lent in the Eastern Orthodox Church and other churches using the Byzantine Rite to commemorate, originally, only the final defeat of iconoclasm on the first Sunday of Lent in 843, and later also opposition to all heterodoxy.