To-day is Septuagesima* Sunday, in the ante-Vatican II roman calendar. The weeks of Epiphany are over. In mass, the Gloria† is not sung. Alleuia†, also awaits the Easter Vigil. Now, we have a movable calendar, in this regard, and the mass readings for the extra Sundays of Epiphany are used for the supplementary masses, after Pentecost, before Advent. This gets complicated, a bit. The readings for the 24th Sunday after Pentecost are always the last before Advent. The 22nd Sunday is always read. If there is less than 24, the 24th is read on the 23rd Sunday and those for the 23rd are read on the Saturday, prior. Now, when there are extra Sundays, the readings for the last Sundays of Epiphany are read, in reverse order, from the last Sunday of Pentecost, until the 23rd. The first supplemental mass has the readings of the 6th Sunday of Epiphany ... the fourth supplemental mass has the readings of the 3rd Sunday of Epiphany. A calendraic year has 52 full weeks and one or two days; so a year may have either 52 or 53 Sundays. Either the 1st of January, or Christmas can fall on Sunday. I am not certain, whether, a year can repeat the same set of Sunday readings; I would think not. The three year vernacular cycle avoids this by having an, interrupted, Ordinary Time, in place of epiphanical, pentecostal time, and three Sundays of pre-Lent.
Now, all movable dates are fixed on the date of Resurrection Sunday, the Paschal feast. Quadragesima is a period of forty days used for fasting and preparation. The term was used at Nicæa (325). Quadragesima Sunday is the first Sunday of Lent. Quinquagesima is the Sunday prior to Lent. Sexagesima is two Sudays prior. Quinquagesima is fifty days, Sexagesima is approximately sixty days, Septuagesima is approximately seventy days before Easter, and in part is to remind us to the years of Babylonian exile, as Quadragesima the forty years in the desert, and the forty days Jesus was in the desert.
*Septuagesima is fun to say.
†Quómodo cantábimus cánticum Dómini in terra aliéna ?
How shall we sing the song of the Lord in a strange land? ― Ps. 136. 4 DRC
There had been an occasional celebration, where in, the day prior to Septuagesima, the choir would take an Alleluia banner through the church and deposit it to rest. Alleluia, dulce carmen was sung.