Sunday of Orthodoxy-1st Sunday of Great Lent

The following is copied from oca.org.

Originally, the Prophets Moses, Aaron, and Samuel were commemorated on this Sunday. The Alleluia verses appointed for today’s Liturgy reflect this older usage.

Today we commemorate the “Triumph of Orthodoxy,” the restoration of the holy icons in the reign of the holy Empress Theodora (February 11).