Processions may be festal or penitential. According to W. use they take place before the principal celebration of the Eucharist on festivals; the ancient English use was for processions to be held after Vespers. Processions are sometimes held in the open air as acts of witness, e.g. on Good Friday. Other traditional processions include those on Palm Sunday, the Rogation Days, and Corpus Christi. In the Byzantine rite a procession is prescribed for Vespers on the eves of Sundays and great feasts. There are also processions with the epitaphion on Good Friday and Holy Saturday, and a procession at the beginning of Mattins in the Midnight Easter Vigil. For processions in the Eucharistic Liturgy, see Gospel; Offertory (1); and Great and Little Entrance.