In Title IV., sect, 1 (see Breviary, Additiones and Variationes) there
is no change in the old rubric. The eight Sundays of the first class
exclude every other feast. And the Sundays of the second class only give
place to a double of the first class and then are commemorated at Lauds,
Vespers and Mass, and have the ninth lesson in Matins.

But section 2 (_Dominicis minoribus_)... goes to the root of the matter
of the new change in the rules for Sunday's liturgical office. The
ordinary Sundays ranked as semi-doubles and hence their Mass and Office
was superseded by the Mass and Office of some occurring feast. The
length of the Sunday office, in the breviaries until lately in use, made
many hearts rejoice over the occurring feast. But the almost total
omission of the ancient and beautiful Sunday Masses was a misfortune
and, in a sense, an unbecoming practice, which broke away from ancient
liturgical rule and tradition. The abbreviation of the Sunday office in
the new breviaries and the rule laid down in Title IV., sect. 2, restore
Sunday's office and Sunday's Mass to their old and proper dignity.

The general rule laid down is that on Sundays throughout the year the
proper office of the Sunday shall always be said. The exceptions are (1)
Feasts of our Lord and their octaves, (2) Doubles of the first class,
(3) Doubles of the second class. On these days the office will be the
office of the feast, with commemoration in Lauds, Vespers and Mass.
Henceforth Sundays are divided into:

(1) Sundays of the first class, which exclude all feasts;

(2) Sundays of the second class, which exclude all feasts save doubles
of the first class;