The Vigil of the Assumption is of simple rite. As the feast falls on Monday this year, the Vigil is anticipated on the Saturday. Traditionally it has been a day of fasting and abstinence in the West (in many Eastern rites a far stricter fast of preparation takes place from the beginning of August). However, such fasting, in the West, never applied to anticipated Vigils. The liturgical colour of the day is violet.
At Mattins everything is taken from the ferial psalter except the lessons. The three lessons in the nocturn on St. Luke's Gospel are from a homily of St. Chrysostom. At Lauds the Second Scheme of psalms is sung (Pss. 50, 91, 63, Audite, caeli & 150), the ferial preces are sung, with the choir kneeling, followed by a commemoration of SS Hippolytus & Cassian and then the Suffrage of the Saints in the form used for feasts of the BVM. At Prime and the Hours ferial preces are sung. These too are sung whilst kneeling. At Prime the fourth psalm is added, as is the case when the Second Scheme of Lauds is sung, and the chapter is the ferial Pacem.
Mass is sung after None. Violet vestments are worn, the ministers wearing dalmatic and tunicle not folded chasubles. The Mass is proper, Vultum tuum, the Gloria is not sung. The second collect is of SS Hipplytus and Cassian, the third collect Deus, qui corda - of the Holy Ghost. As it is a 'kneeling day' all in choir kneel for the orations and from the Sanctus to the response after Pax Domini. As is the rule when the Gloria is not sung Benedicamus Domino is chanted as the dismissal by the deacon facing the altar rather than Ite, missa est.
In the afternoon there is a colour change to green and Vespers of Saturday are sung. The antiphon on the Magnificat is Omnis sapientia for the Saturday before the third Sunday of August. A commemoration is sung of St. Eusebius followed by the Suffrage of the Saints. At Compline the Dominical preces are sung.
In the ancient use 'liturgical books of 1962' as usual much has been lost. Common Vigils are not anticipated so this year the Vigil of the Assumption is omitted entirely. The day becomes a IV class BVM on Saturday. At Vespers the antiphon on the Magnificat is Ego in altissimis - as sung last week in the old rite - the Suffrage is omitted as are the preces at Compline.