IV Concerning Octaves
In the Lists at the end of these Rubrics are noted the Feasts which in this Breviary are accorded simple or common or privileged Octaves, and in their respective Propers will be found directions for keeping their Octaves. However, other Feasts are in certain places given Octaves (e.g., Feasts of the Title, Dedication, Patron etc.), which same are kept according to the rules of similar Octaves in this Breviary.
Privileged Octaves govern the Office of their Sundays according to the directions of their several Rubrics, but common Octaves do not, i.e., the ordinary Sunday Office is said, with a Commemoration of the Octave, as far as the rules of Concurrence and Occurrence permit.
All Octaves are subject to the following general rules:-
1. Octaves are preferred among themselves according to the same rule as the Feasts to which they pertain.
2. The Octaves of I Class Double Feasts of Our Lord, if they are celebrated in the Universal Church with an Octave are known as privileged Octaves because of this privilege, viz., that their full Office or its Commemoration, is always to be said of them, as is stated at greater length in the particular Rubrics of their several Offices.
3. The Octaves of other I Class Doubles are common Octaves, (even those of a patronal Feast, or of a Feast of our Lord not included in section 2 above,) and are sometimes omitted in whole or in part, as is said in section 5 below. Otherwise, unless they are impeded by an Office of higher rank, the whole Octave is celebrated with semidouble rite on the days within the Octave, and with greater double rite on the Octave Day.
4. The Octaves of II Class Doubles are simple Octaves, and these have no days within the Octave, i.e., the Feast is kept as a II Class Double, and the Octave Day is kept as a Simple but otherwise the Octave is ignored.
5. If a Feast having an Octave be transferred, its Octave is not transferred, but only so much of its Octave as remains; for which reason, if it be transferred outside its own Octave, no Octave is kept. (This rule, however, does not apply to the Feasts of the Holy Name or Holy Family if they should be transferred and kept with an Octave.)
6. From the Tables of Concurrence and Occurrence, it can be seen in what way Octave Days and days within Octaves are given preference over other Feasts; but it should be noted that although Days within Octaves are ranked only as Semidoubles, nevertheless on such days, even when only commemorated, neither the dominical Preces nor the Common Commemoration are to be said; and in like manner they are omitted also on a simple Octave Day, even commemorated. (After None, of course, there is no observance or commemoration of a simple Octave Day.)
7. During certain seasons no Octaves my be celebrated, viz., from Dec. 16th until the Vigil of Christmas, and from Ash Wednesday until Low Sunday, and from the Vigil ofg Pentecost until Trinity Sunday, all inclusive; for which reason any Octave which may be in process of observance (or of commemoration) is terminated with Compline of Dec. 15th, or of Shrove Tuesday, or of Friday after the Ascension Octave, as the case may be.
8. The rules for commemorating a day day within an Octave will be found below in Rubric X, Concerning Commemorations, sections 4 and 5.