Pius Parsch once cogently argued that the Liturgical Year - the Church's Year of Grace - doesn't begin with Advent Sunday, but with Septuagesima Sunday!
For at Septuagesima, the Matins Lesson begin "In the beginning...", with Genesis chapter one, verse one. The sober liturgy proceeds through the account of Man's Creation and Fall, and then through the Patriarchs and God's continual call of them back from doom to salvation - at Sexagesima, Noë and the Flood; at Quinquagesima, the call of Abraham.
(The Mozarabic Liturgy for Lent similarly proceeds through the Books of Moses and those of the Kings, but on a much more fulsome scale, with long readings even at the Little Hours, concluding with the Fall of Jerusalem, symbolic of Israel's persistent and final failure to keep the Law, of the ultimate frustration of the Old Testament without the grace of the New. But even then, the Return from Exile in Babylon, and the comforting words of the prophets, foretell the Messianic Age when all Israel shall be saved.)
We cannot begin the New Year of Grace, without remembering how for Man it all started so well, and so quickly went so bad - we cannot begin the New Year of Grace without in sombre recollection thinking on our own sin. We spend the time from now through till Easter turned toward the Lord, conscious of our need and insufficiency, conscious of His mercy and His making speed to save us.
We do not so much put away Alleluia for a time, as begin the Year with it - at first Vespers of Septuagesima (once at the start, and four times at the end with the Benedicamus Domino otherwise special to Paschaltide), signifying that "In the beginning" Man and all that God created was "very good" (as in the Dominican Office the special Responsory at first Vespers tells) - then immediately leave it aside (symbolizing the Fall and the consequent captivity of all men under sin) till Christ by His Victory, bursting forth from the tomb on Easter morn, restores all things in Himself, making all things new.
"Alleluia, our transgressions / Make us for a while give o'er..."
The mediævals called this the Depositio Alleluia, the burial, even of the Alleluia - for as Adam sinned and died and was buried, so the heavenly song of original justice must be laid aside. (Some local ceremonies of old time for this involved writing Alleluia on parchment, and actually burying it!)
At Easter, all that had been foreshadowed is accomplished: "freed from Pharaoh's bitter yoke, Jacob's sons and daughters" - by the new Moses, Our Saviour, Who leads us through the waters of Baptism. With Him as Shepherd and Guide, we set forth for the Promised Land...
We celebrate for fifty days the glory of the Resurrection, which is our resurrection, laying hold on it by grace - for Christ stretches forth His hand to draw us also, like Lazarus, from the tomb.
Pentecost is the Gift of the Spirit, completing the Paschal Mystery; after Pentecost, we live through the Ages of the Church; Advent is the season of looking forward to the Return of Christ; at Christmas and Epiphany, we ought not so much indulge in mawkish fawning upon "the Little Boy Jesus / Asleep on the hay" as see in Him our Goal, as see these feasts as prefigurations of the glory that is to come, that in Heaven we shall be united forever with the Lamb of God, "casting down [our] golden crowns" before Him.
The conclusion of the Liturgical Year, then, is not Stir-up Sunday, nor Christ the King (for, He reigns now, as He has for all ages as God, and as Incarnate Deity enthroned above since His Ascension, His return back to His Father in robes of glory, His Sacred Humanity: Christ the King ought not be an eschatological safe dream, but our motto for life in this age - Viva Cristo Rey!).
The End of the Liturgical Year is Candlemas, the Meeting with Christ in the Temple - when we too, as Simeon, can say Nunc dimittis.
How happy it is that Candlemas and Septuagesima Sunday so often overlap, as they do this year (2nd February and 31st January) - the Liturgical Year is the image, repeated for our edification and sanctification, until the Lord completes the cycle in us by our death, and in the Church by His Return in glory. When we are judged, though like Adam, and ancient Israel, and the new Israel, the Church in her members, we will admit many falls and backslidings, may we in our own persons attest that God's grace is stronger than human weakness: "And all things shall be well, and all manner of things shall be well."
(Need I add that for sundry reasons, it seemed good and fitting to go to confession and disburden myself this morning?)