"Ave Regina caelorum" is one of the Marian antiphons said or sung in the Liturgy of the Hours at the close of compline. In the Roman Breviary as revised by Pope Pius V in 1569 it was assigned for this use from compline of 2 February until compline of Wednesday of Holy Week. Since the revision of the Liturgy of the Hours in 1969, the only Marian antiphon for whose use a fixed period is laid down is the Easter season antiphon Regina caeli. The prayer, whose author is unknown, is found in manuscripts from the twelfth century onward.