THE LITURGICAL CALENDAR
The document below explains how there are two concurrent cycles of feasts of the Liturgical year, the "temporal cycle" (Temporale) or "Proper of the time" (Proprium de tempore) and "sanctoral" (sanctus) cycles. The temporal cycle is an annual cycle during which
the Church celebrates the whole mystery of Christ, from the Incarnation to Pentecost Day and the days of waiting for the Advent of the Lord (GNLYC, No. 17)
The source and center of the whole Liturgical Year is the Paschal Mystery. The annual commemoration centers on that mystery, and then spirals out with the whole mystery of Christ. In the order of prominence the temporal cycle is composed of the Easter Triduum, Easter Season, Lent, Christmas Season, Advent, and Ordinary Time. The temporal cycle also includes solemnities and feasts that celebrate the mystery of the Redemption. This cycle needs to be preserved and remain intact to "enjoy its rightful preeminence over particular celebrations" (GNLYC, No. 50a).
And then there is the sanctoral calendar, or the Proper of the Saints which includes feasts of devotion of Our Lord, feasts of Mary and the saints. This cycle runs simultaneously with the temporal cycle, but it is secondary in the priority of feasts.