The important church in the world dedicated to the Holy Virgin this is the only of the 4 papal basilicas dedicated to a woman.

Tradition has it that the Virgin Mary herself inspired the choice of the Esquiline Hill for the church's construction. Appearing in a dream to both the Patrician John and Pope Liberius, she asked that a church be built in her honor in a place that she would miraculously indicate. The morning of August 5th, the Esquiline Hill was covered with a blanket of snow. The pope traced the perimeter and John financed the construction of the new church. Nothing remains of this church but a few lines in the Liber Pontificalis affirming that Pope Liberius "Fecit basilicam nomini suo iuxta Macellum Liviae."