Siglum: 
I-Rvat Capp.Sist.27
Summary: 
Antiphoner copied during the reign of Pope Julius II (probably 1510) for use in the Sistine Chapel. Staff notation. Covers only the beginning of the liturgical year (ends at Octave of Epiphany). 149 folios.
Liturgical occasions: 
Ff. 1-148: Temporale and Sanctorale together: 2r, First Sunday of Advent; 37r, Great "O" Antiphons; 70r, Christmas; 107v, Stephen; 111r, John the Evangelist; 115v, Holy Innocents; 119v, Thomas Becket; 122r, Silvester; 128v, Epiphany; 142v, Octave of Epiphany. F. 149, blank.
Description: 

The manuscript usually includes only the chants for Lauds and Vespers, and the Little Hours in some cases (First Sunday of Advent, Christmas Eve, Christmas, and Epiphany). Christmas is the only feast to have a Matins service (ff. 73r-96v). Therefore, the only invitatory in the manuscript is the one assigned to Christmas, and it is accompanied by a complete invitatory psalm tone (ff. 73r-79r). The indexer has assigned numbers arbitrarily to the manuscript's differentiae. Only the second differentia in mode 1 seemed problematic: erasures (ff. 12r, 14r) indicate that the form of this differentia was altered by a later hand. Its original form was probably similar, if not identical, to the differentia (1.3) assigned to "Inclinavit dominus aurem suam" (13r), which appears nowhere else in the source. When this antiphon occurs again later in the manuscript (44v), it is assigned the revised form of 1.2, indicating that the editing scribe apparently neglected to change the differentia on 13r. No attempt has been made to represent the erasures in the index. Some antiphons in the manuscript (ff. 14r, 18r, 28v, 35r, 80r) appear to have the mode 1 intonation, but no differentia. This may indicate the second differentia which, in its altered form, is given as A-A-A-A-A-A. The index, however, indicates only that there is no differentia for these chants. Two other antiphons (ff. 130r, 131r) are assigned what appears to be a slightly different form of this differentia, perhaps in a later hand. Probably because there are so few antiphons in the manuscript, three other differentiae occur only once: 4.2, "Sion noli timere ecce deus" (19r); 4.3, "Ad te domine levavi" (55v); and 7.3, "Stella ista sicut flamma" (131v). Comparison with other manuscripts in the CANTUS database confirms that these antiphons are commonly associated with unusual differentiae.

The manuscript has no Ferial Office. However, some ferial antiphons--one series for Lauds and one for Vespers (ff. 11r-14r)--are intended to be sung on all week days during the first three weeks of Advent (but not the final week, which has its own proper antiphons for Lauds, according to the rubric on 10v).

The foliation in the index follows the more recent foliation (small Arabic numerals in each recto's lower margin) rather than the earlier one (the Roman numerals in the right margin, which include two misfoliations).

All chants not included in CAO have been assigned a number prefixed by "rvs".

Indexing notes: 
The index for I-Rvat Capp.Sist.27 was prepared at The Catholic University of America by Charles Downey.