The stillness on the high mountain told him that this was the place. After following the Camino de Santiago and wandering through Italy with the dream of reaching Jerusalem, William of Vercelli reached Irpinia and felt a strong call to that mountain covered in woods.

Entering the greenery, he came across a small valley which seemed to him ideal for staying to meditate and pray in the contemplation of a landscape of great beauty. Built a small cell, he retired in solitude and in harmony with the wild nature, visited by wolves and bears without being attacked. And a wolf, moreover, will be the protagonist of one of the miracles attributed to him in the process of sanctification, which is why he will usually be depicted with the wild animal at his side. The presence of William, already smelling of sanctity, attracted other men eager to retire from the world on Partenio, which in that place had taken the name of Montevergine.

With mud and stones other cells were built and a small monastic community was formed. It soon devoted itself to building a church, consecrated in 1126 and dedicated to the Madonna for the deep devotion of William and the other monks. The group of hermits gave life to a new congregation, known as the Verginiana of the Order of Saint Benedict, recognized by Pope Leo XIII in 1879, which engaged above all in the evangelization of the people and in the construction of hospitals in various areas of Campania and also outside.

After William's death, which took place on 25 June 1142 in Goleto near Nusco, the sanctuary experienced a long golden age until the mid-1300s. In that period the church was embellished with important works of art resulting from donations from the faithful, including the painting of the Madonna. And a valuable Romanesque canopy with Cosmatesque inlays from the 13th century, a gift from Maria of Hungary or perhaps from her son Carlo Martello of Anjou. Also of great artistic value is the funeral monument of Catherine II of Valois, wife of Philip of Anjou, and her children. Among the relics kept in Montevergine, also the bones of San Gennaro, later transferred to the Cathedral of Naples. From the second half of the 1300s to the end of the 1500s, two centuries of decline, including religious decline, followed in the Sanctuary, which in 1629 was heavily damaged by the collapse of the central nave, so much so that it had to be rebuilt in 1645 based on a project by the architect Giacomo Conforti. At the beginning of the 19th century, the confiscation of the assets of the religious orders was a severe blow, which was overcome after the unification of Italy, when it was sanctioned that the provision did not concern the abbeys and thus the sanctuary of Irpinia also benefited from the restitution of the confiscated assets.

During the Second World War, the Shroud was kept safe at the Sanctuary of Montevergine. Then, after the war, renovation work was carried out on the guesthouse and sanctuary and in 1956 the funicular connecting with the center of Mercogliano was built. Begun in 1952, the new basilica was inaugurated in 1961 based on a project by the architect Florestano Di Fausto. Then the painting of the Madonna was transferred and placed on the high altar, but in 2012 it was brought back to the ancient church. Also modern is the crypt that housed the remains of San Guglielmo, brought to Montevergine from Goleto in 1807 by order of Gioacchino Murat. The museum displays archaeological finds from the Roman era recovered in the vicinity of the sanctuary, where in ancient times there was a temple to the goddess Cybele, and works of art donated over time by pilgrims. Even today many of them go up to the sanctuary at over a thousand meters above sea level, in a magnificent place from which you can admire a large part of the Irpinia landscape.