In the middle of the 1300s, after about five centuries, the plague returned to Europe. It was a devastating epidemic; it has been estimated that between 1348 and 1351 it led to the death of approximately 30 million out of a total of 100 million people. “Compagnie dei bianchi” or “white companies” were formed: multitudes of men and women, who wore white linen hooded tunics over their clothes, walked in procession from one sanctuary to another, beating themselves as a sign of penitence, praying above all to the Virgin Mary in the name of the Madonna della Misericordia, or Madonna of Mercy. Word spread through the Fermano area that if a round church was built in just one night and named “Madonna della Misericordia”, the contagion would cease.
In the middle of the 15th century, a small round church with a small dome dedicated to the Madonna della Misericordia was also built in Monteleone. On the main altar of this church, the central fresco represents the Madonna sheltering the faithful under her cloak, above an image of the town. The church was extended in 1526 on the foundations of the previous Roman church, and consecrated on 27 May 1543. All the external walls are decorated with pilaster strips and woven hanging arches supported by corbels; the central and two side apses maintain their original stonework. Above there is a bell gable, with a bell, both of 1640. The inside is entirely painted with frescoes and tempera; it represents the most extended pictorial cycle preserved in the Fermano area. The Last Judgement, realised in 1548 by Orfeo Presutti of Fano, is especially fine. It is a didactic work, which shows the congregation what will happen to them in the afterlife, and the decidedly fierce punishments that will be dealt out for each sin. The painter describes the geography of the afterlife, showing us places that are well-known in traditional sermons: earthly paradise, purgatory, rivers of hell, the city of Satan. In the entrance, on the right, there is a beautiful wooden statue of St. Rocco, protector against the plague, from the 16th century.