June 17th - Trinity Sunday

The Feast of the Most Holy Trinity is a double feast and its liturgical colour is white. It is also the first Sunday after Pentecost.

At first Vespers on Saturday afternoon the Office was proper with the antiphons Gloria tibi Trinitas etc sung with Pss. 109, 110, 111, 112 and 116. The chapter, O altitudo, and hymn, O lux beata Trinitas, will be used at Vespers on Saturdays for all the Sundays after Pentecost when the following Office if of the Sunday. The antiphon on the Magnificat, Gratias tibi, Deus etc, and the collect, Omnipotens, were proper to the feast. After the collect of the feast a commemoration was sung of the first Sunday after Pentecost. After Vespers the antiphon Salve Regina was sung for the first time this year.

At Mattins there are three nocturns. The invitatory is proper, Deum verum, unum in Trinitate, et Trinitatm in Unitate, Venite adoremus. The hymn is Summae Deus clementiae. In the first nocturn the antiphons Adesto unus Deus etc are sung with psalms 8, 18 & 23. The lessons are taken from the sixth chapter of the Prophet Isaiah. These are identical to those found in the 'modern' books. In the second nocturn the antiphons Te invocamus etc are sung with psalms 46, 47 & 51. The lessons are taken from the Book of Bishop Fulgentius on faith. The fourth lesson continues with Si enim, sicut et Patris...veraciter Trinitas diceretur. The fifth lesson begins Rursus quidem Trinitas...and continues Per hanc unitatem...totus quoque Spiritus Sanctus in Patre et Filio. The sixth lesson begins Nullus horum and continues past the ending found in the 'modern' editions with three more sentences Sicut ergo...est trium personarum divinitas. In the third nocturn the antiphons Caritas Pater est etc are sung with psalms 95, 96 & 97. The lessons are from a homily of St. Gregory Nazianzen. These are again slightly longer than those found in the 'modern' editions. The seventh lesson continues Nec extensionem...atque potentiae credimus. The eighth lesson begins Et ideo unum... and continues Sic est Apostolus...per quem omnia et nos per ipsum. The ninth lesson is of the first Sunday after Pentecost, it ends slightly before the version in 'modern' editions with Ego sum panis vivus, qui de caelo descendi? The Te Deum is sung.

At Lauds the antiphons Gloria tibi Trinitas are sung with the Dominical psalms 92, 99, 62-66, Benedicite & 148-149-150. The Office hymn is Tu, Trinitatis Unitas. After the collect of the feast a commemoration of the first Sunday after Pentecost.

At Prime the festal psalms are sung (53, 118i & 118ii). Quicumque is sung after the last stanza of Ps. 118. The Creed is sung on all Sundays when the Office is of the Sunday unlike in the later reformed versions of the rite. The Dominical preces are omitted.

Mass is sung after Terce. Before Mass at the sprinkling of lustral water the antiphon Asperges me returns. The Mass is proper, Benedicta sit. The Gloria is sung, the second collect is of the Sunday, the Credo is sung, the common preface is sung, and the last Gospel is of the Sunday.

At second Vespers the antiphons Gloria tibi Trinitas etc are sung with psalms 109, 110, 111, 112 & 113. The chapter is O altitudo and the Office hymn O lux beata Trinitas. After the collect of the feast a commemoration of the first Sunday after Pentecost is sung followed by a commemoration of SS Mark and Marcellianus. At Compline the Dominical preces are omitted.

Art: Rublev's Icon from Wikipedia, the Hospitality of Abraham iterpreted as a symbol of the Trinity.