Western Catholic liturgy assigns four Marian antiphons to the close of the daily office, Compline, rotating through the church year by season rather than being recited identically year round. Alma Redemptoris Mater covers the longest and earliest span, sung from the first Sunday of Advent through the Feast of the Presentation on the second of February, making it in practical terms the antiphon a religious community would sing more nights of the winter than any of the other three. It is followed through Lent by Ave Regina Caelorum, then through the fifty days of Eastertide by Regina Caeli, already catalogued in this atlas, before the year's longest season, Ordinary Time from Trinity Sunday to Advent, is carried by the best known of the four, Salve Regina, also already catalogued here.
Manuscript evidence places Alma Redemptoris Mater's composition in the eleventh century, making it the oldest of the four antiphons in this seasonal rotation, predating the Regina Caeli's written appearance by roughly a century and the Salve Regina's spread by a comparable margin. Its brevity, four lines addressing Mary as gate of heaven and star of the sea before asking her help for a fallen and rising people, sits at the plainer end of the four antiphons stylistically, closer to a compact devotional formula than to the more elaborated address found in the Salve Regina's longer text.