I would just like to point out, if I may, that the immaculate Conception superseding a Sunday in Advent is a peculiarity of the 1962 calendar. In the calendar before that, Sundays in Advent superseded the Immaculate Conception.
A
few calendars before that.
Pope St. Pius V made it such that the Sundays of Advent and Lent were utterly inviolable (like they are today in the 1969 rubrics), and this was changed by Pope St. Pius X in the early 20th century, a few ordos before the General Roman Calendar of 1960 and the restructuring of feasts using the 1st/2nd/3rd Class system. In fact, during this time The Immaculate Conception still technically
outranked the Sundays of Advent (Immaculate Conception was a 1st Class Double while Adventen and Lenten Sundays were 2nd Class Doubles) but the rubrics specified these Sundays as nevertheless impeding higher classed feasts.
Pope St. Pius X made it such that the higher ranked feasts (1st Class Doubles) impede the lower ranked Sundays (2nd Class Doubles) in 1913, then Venerable Pope Pius XII raised the Adventen/Lenten Sundays to 1st Class Double in 1955, effectively undoing what Pope St. Pius X did with the relative impediments of the feasts. In 1960 Pope St. John XXIII completely restructured the complex ranking schema with a simplified 1st/2nd/3rd Class system (classes that would later be renamed to Solemnity/Feast/Memorial respectively by Pope St. Paul VI). This rendered both the Adventen Sundays and the Immaculate Conception as 1st Class Feasts, whose relative position in precedence was governed by the General Rubrics of the Roman Mass & Breviary (1960) in which the Immaculate Conception once again explicitly (
and uniquely) outranked the Sundays of Advent.
Finally, Pope St. Paul VI reverted the ordo back to the practice of Adventen/Lenten Sundays being utterly inviolable as was the case in Pope St. Pius V’s day. Long story short: this is one of those rare instances where the so called Novus Ordo is actually
more traditional than the TLM of 1962.
Honestly, this makes much more sense to me. Without Mother Mary’s Immaculate Conception, there wouldn’t BE an Advent.
I personally take the opposite position: Mother Mary wouldn’t have been immaculately conceived if there was never an Advent of Our Lord, since her Immaculate Conception occurred due to the anticipated application of the merits of Our Lord’s Passion, which in turn could never have occurred had he never come in the flesh in the first place, but I suppose that puts us in a sort of theological chicken/egg paradox.
