The church of Saint-Etienne-du-Mont originated in the abbey of Sainte-Genevieve, where the eponymous saint had been buried in the 6th century. Devoted to the Virgin Mary, then to St. John the Apostle, the place was too small to accommodate all the faithful. In 1222, Pope Honorius III authorized the establishment of an autonomous church, which was devoted this time to St Etienne, then the patron saint of the old cathedral of Paris.
Soon, the new building was overwhelmed by an increasingly dense population: the Sorbonne and many colleges were located on the territory of the parish. It was enlarged in 1328, but a complete reconstruction became necessary from the 15th century. In 1492, the monks Génovéfains donated a portion of their land for the construction of the new church.