Monday in the Paschal Octave is a Double of the First Class and a suppressed holyday. This year it is also the Greater Litanies. The feast of St. Mark is transferred out of the Octave to the 4th May in the Universal Kalendar (in England to the 5th May as St. George is transferred from Holy Saturday to the 2nd May, SS Philip and James to the 4th May).
The Office is essentially the same as the feast of Easter with some parts proper to the day. At Mattins the invitatory, antiphons and psalms (1, 2 & 3) are sung as yesterday. The three lessons and responsories are proper to the Monday. The Te Deum is sung to the solemn tone where possible. At Lauds the same antiphons and psalms are sung as yesterday. The Haec dies is sung as yesterday in place of the chapter and hymn. The antiphon on the Benedictus and the collect are proper to the Monday.
At Prime and the Hours festal psalmody is sung to the special Paschal Tone 2 chant, the structure of the Hours is as yesterday, the collect proper to the Monday.
Mass is sung after Terce. The Mass is proper. The Gloria is sung, there is a commemoration of the Greater Litanies, the Creed is sung, the preface is of Easter, the Communicantes and Hanc igitur in the Canon are of Easter. Again Ite, missa est, alleluia, alleluia is the dismissal.
In Cathedral and Collegiate Churches two High Masses are celebrated today. The first Mass, sung after Terce is of that of the Monday in the Paschal Octave with Gloria, one collect, Sequence, Creed, Paschal preface etc with festal tones throughout and the Paschal Candle is lit. The Mass is, of course, sung in white vestments.
After None the sacristy team, exhausted by the Triduum, have to extinguish the Paschal Candle, change the altar antependia from white to violet and find the vestment sets last used in Quinquagesima consisting of violet dalmatic and tunicle. The celebrant, vested in violet cope, assisted by deacon and subdeacon in violet dalmatic and tunicle reverence the altar then kneel and pray for a short while. They rise and the cantors begin the antiphon Exsurge Domine. The choir continue....adjuva nos, et libera nos, propter nomen tuam. Ps. Deus auribus nostris audivimus patres nostri annuntiaverunt nobis. Gloria Patri etc, Sicut erat etc and then Exsurge Domine is repeated. All all kneel (except the crucifer and acolytes who go and stand at the entrance of the choir) and the cantors then begin the Litany of the Saints. This is sung in the full form, and not the shorter form used on Holy Saturday two days ago. Each invocation is doubled, i.e. the cantors sing e.g. Pater de caelis, Deus, miserere nobis and this is repeated in its entirety by everyone else. When Sancta Maria, ora pro nobis has been repeated all rise and the Procession sets off.
The Procession goes outside of the Church and may visit other Churches on its route. In this case the celebrant is offered lustral water at the entrance to the church and processes to the High Altar. After a moment for silent prayer the choir signs the antiphon of the patron of the church, its versicle and response (with Alleluia added as it is Paschaltide) and the celebrant sings the collect of the Patron. The Litany is then resumed and the Procession continues. If the Procession has a long route the Litany, from Sancta Maria etc may be repeated or the Seven Penitential Psalms sung to the tonus in directum. When the Procession enters the church where Mass will be celebrated, lustral water is received on entering and the Procession goes to the sanctuary. All kneel as the Litany ends. The celebrant intones Pater noster etc and then the cantors sing psalm 69. After the versicles that follow the celebrant stands to sing the ten collects. He then kneels again as Exadiat nos etc is sung. The ministers then rise and the celebrant changes from a cope to chasuble and all put on their maniples. The Mass Exaudivit is then sung. The chants are those used for ferial Masses. The Gloria is not sung, there are the additional prayers of the season. There is no Creed. The preface of Paschaltide is sung to the ferial tone, the dismissal is Benedicamus Domino.
Where only one Mass is sung and the Procession takes place after the Procession the celebrant and ministers change their violet vestments to white vestments and the Mass for the Monday in the Paschal Octave is sung with a commemoration of the Rogations sung under one conclusion with the collect of the day. The rest is as described above for the first Mass.
Vespers are as on the feast. The antiphon on the Magnificat and collect are proper.
Users of the 'liturgical books of 1962' transfer the Greater Litanies to tomorrow. In the traditional rite if the Greater Litanies fall on holy Pascha they are transferred to the Tuesday but in 1962 if they fall on holy Pascha or the Monday they move to the Tuesday, R.G. 80. St. Mark is simply ignored this year in their Universal Kalendar.