Christ and St. Thomas
The Sunday which follows Pascha (the Second Sunday of Pascha) is called 'Thomas Sunday', because it recounts the appearance of Jesus to the Apostle Thomas eight days after his resurrection (John 20:19-29).
Thomas Sunday is also called 'Antipascha' (literally, 'in the place of Pascha') because those who for honorable reason were not able to attend the Paschal Vigil, may attend services on this day instead. Pascha is a unique feast in the church year, being the 'Feast of Feasts' it follows a format unlike any other day. Those liturgical elements normal to a Great Feast of the Lord which were displaced by Pascha's unique elements are instead chanted on Thomas Sunday.