The Octave-Day of the feast of the Nativity of the BVM is of double rite and its liturgical colour, from Mattins, is white. The double feast outranks the semi-double sixteenth Sunday after Pentecost which, this year, is the third Sunday of September.
At Vespers yesterday afternoon second Vespers of the feast of the Exaltation of the Holy Cross were sung. The antiphons O magnum pietatis opus etc were sung, doubled, with Pss. 109, 110, 111, 112 & 116. The Office hymn was Vexilla regis. After the collect of the feast commemorations were sung of the following Octave-Day, of the Sunday (the antiphon on the Magnificat being Ne reminiscaris for the Saturday before the third Sunday of September) and of St. Nicomedes. The Suffrages were omitted as were the Dominical preces at Compline. Hymn of Iambic metre, throughout the Octave have been sung with the Doxology Gloria tibi Domine etc.
At Mattins the invitatory is Nativitatem Virginis Mariae celebremus: * Christum ejus Filium adoremus Dominum and the Office hymn is Quem terra. In the first nocturn the antiphons Benedicta tu etc are sung with Pss. 8, 18 & 23. The lessons are from occurring Scripture, the Incipit of the Book of Tobias, with the responsories of the feast. The first lesson continues with what, in the post-Clementine editions, the beginning of the second lesson Deinique, cum irent... to ...ministraret omnem decimationem. The second lesson begins Haec et his similia.. to ... salutis dabat eis, what is the end of the third lesson in the later editions. The third lesson, absent from modern editions, begins Cum autem venisset... and continues until ...solicitus exhibebat. (vv. 16 - 20). In the second nocturn the antiphons Specie tua etc are sung with Pss. 44, 45 & 86. The lessons are taken from the writing of St. Cyril of Jerusalem. In the third nocturn the antiphons Gaude, Maria Virgo etc are sung with Pss. 95, 96 & 97. The homily is from St. Chrysostom on St. Luke's Gospel. The ninth lesson is formed of the three lessons of the homily for the Sunday, from St. Ambrose on St. Luke. These are slightly longer than those found in the post-Clementine editions. The Te Deum is sung.
At Lauds the antiphons Nativitas gloriosae etc are sung with Pss. 92, 99, 62-66, Benedicite, 148-149-150. The Office hymn is O gloriosa Domina. After the collect of the feast commemorations are sung of the Sunday and of St. Nicomedes. The Suffrages are omitted.
At Prime the first of the antiphons sung at Lauds is sung with Pss. 53, 118i & 118ii. The lectio brevis is In plateis. Both Quicumque and the Dominical preces are omitted. The other Hours have the antiphons of Lauds sung in the usual order.
Mass is sung after Terce. The Gloria is sung, the second collect is of the Sunday, the third collect is of St. Nicomedes. The Creed is sung, the preface is of the BVM and the last Gospel is of the Sunday.
At Vespers the antiphons Nativitas gloriosae etc., are sung with Pss. 109, 112, 121, 126 & 147. The Office hymn is Ave, maris stella. After the collect of the Octave-Day commemorations are sung of the Sunday, of SS Cornelius and Cyprian and of SS Euphemia and Others. The Suffrages are omitted as are the Dominical preces at Compline.