The appellation of this church is confusing to many - it means that this is Rome's major or principal church dedicated to St Mary.
The first church here was founded c. 350 by
Pope Liberius, and financed by a Roman patrician and his wife. They were childless, and had decided to leave their fortune to the Blessed Virgin. She appeared to them in a dream and told them to build a church in her honor. It lies on the summit of the
Esquiline Hill, which was mainly laid out as gardens in ancient times. Legend claims that the plan of the church was outlined by a miraculous snowfall in August (possibly in 358). The legend is commemorated every year on August 5th, when white rose petals are dropped from the dome during the festal Mass.
The basilica is also known as Basilica Liberiana after the founder, and Santa Maria della Neve, Our Lady of the Snow, after the miracle; and as Santa Maria ad Praesepem after the relic of the crib (presepio).
Pope Sixtus III had the church restored, or more likely rebuilt, to commemorate the declaration of St Mary's Divine Motherhood by the
Council of Ephesus in 432.
The church was damaged in the earthquake of 1348, and restored some years later.
As in the other patriarchal basilicas, there is a Chapter of Canons here. In addition, Redemptorists assist as sacristans, and a 'college' of Dominicans, speaking several different languages, hear confessions most of the day.