How "Advent" Fits Into the Church Calendar Puzzle

"Perhaps the most important single characteristic of the annual calendar presupposed by the ecumenical lectionary is its Christological center. The annual sequence of seasons is actually a pairing of two Christ-celebrations: (1) Christmas and (2) Easter, (1) Incarnation and (2) Redemption. The Christmas celebration is prepared for in Advent and reflected in Epiphany. The Easter celebration is prepared for in Lent and reflected in the fifty days following, which climax in Pentecost. In this sense the Christian Year may be described as the annual rehearsal of the history of our salvation accomplished in the birth, death, resurrection, and return of Jesus Christ" (Horace T. Allen Jr., A Handbook for the Lectionary, 25).