Catechism of the Catholic Church §1171 — excerpt
In the liturgical year the various aspects of the one Paschal mystery unfold. This is also the case with the cycle of feasts surrounding the mystery of the incarnation (Annunciation, Christmas, Epiphany).
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.