The Epiphany, or Theophany in the East, is a Double of the First Class with a privileged Octave of the Second Order.
The Epiphany was kept in the East from the third century, or earlier, and spread to the West a century later. Originally, it seems, in the East at least that this 'manifestation' of the LORD was the same celebration as the Nativity. To this day those following the Armenian Rite keep Christmas-Theophany today.
That the feast is ancient is clearly seen in the structure of the Office of Mattins, unique to this day. The (historically later) Domine labia me, invitatory and hymn are ommitted and the Office begins with the first antiphon Afferte Domino. Psalm 94, Venite , is sung in the third nocturn, in a responsorial manner, with the verse Venite, adoremus eum: quia ipse est Dominus, Deus noster. The psalmody is festal. At Prime in the short responsory a versicle Qui apparuisti hodie is sung and for the Octave. At Vespers and Lauds six pluvilistae in pariti assist the Hebdomadarius.
At Mass the Gloria and Credo are sung. The preface and communicantes in the Canon are proper to the feast. According to the rubrics of the Graduale four cantors lead the choir today.
After the Gospel the Moveable Feasts for the year are traditionally announced. The chant is very beautiful. The text is as follows:
Noveritis, fratres carissimi, quod annuente Dei misericordia, sicut de Nativitate DNJC gavisi sumus, ita et de Resurrectione ejusdem Salvatoris Nostri gaudium vobis annuntiamus.
Die octava Februarii, erit Dominica in Septuagesima.
Vigesima quinta Februarii, Dies Cinerum et initium jejunii Sacratissimæ
Duodecima Aprilis, Sanctum Pascha DNJC cum gaudio celebrabimus.
Vicesima prima Maji, erit Ascensio DNJC.
Trigesima prima Maji, Festum Pentecostes.
Undecima Junii, Festum Sacratissimi Corporis Christi.
Vigesima nona Novembris, Dominica prima Adventus DNJC, cui est honor et gloria in sæcula sæculorum. Amen.
Vespers are of the feast.
In the 'liturgical books of 1962' the only textual changes are the abolition of the Doxology in honour of the Epiphany at the hymns of the Little Hours and the duplication of antiphons at the same.