[2] Prior to the Second Vatican Council (1962-65), as a general rule, churches in which the Divine office was to be said publicly every day also had to have Mass said daily.
That friars celebrated a daily conventual Mass according to the rule of monastic churches is admitted by every one (de Herdt., I, 14).
[2] The obligation of procuring the conventual Mass rested with the corporate body in question and so concerns its superiors (Dean, Provost, Abbot, etc.).
Except in Advent, Lent and Paschal time, on the first day of the month not prevented by a double or semi-double, the conventual Mass was a Requiem for deceased members and benefactors of the community.
On Ascension eve, if a double or semi-double occurs, the Mass of the feast was said after Terce, that of the Vigil after Sext, that of Rogation after None.
When an additional votive Mass had to be said (for instance for the Forty Hours or for the anniversary of the bishop's consecration or enthronement, etc.)
On the Monday of each week (except in Lent and Paschal time) if the office was ferial the conventual Mass was permitted to be a Requiem.
Regulars were not bound to celebrate more than one such Mass each day (corresponding always to the office), unless the particular constitutions of their order imposed this obligation.