After the Feast of the Presentation of the Lord (usually celebrated February 2), the Marian Anthem sung till Easter Vigil is traditionally the Ave Regina Caelorum.
It dates back to Monastic traditions popular from around the 12th century. Herman Contractus (approx. AD 1054) is often suggested as the author although it is not entirely certain. This antiphon is one of the traditional concluding antiphons for Compline.
Hail, Queen of heaven,
hail Lady of the angels.
Hail root and gate from which the Light of the world was born.
Rejoice glorious Virgin, fairest of all.
Fare thee well, most beautiful, and pray for us to Christ.
Download the Ave Regina Caelorum chant sheet here.