The façade of this building was never completed. Built between the end of the 15 century and th the early 16 century, it presents the typical features of Catalan late-Gothic style: a hall marked by bays with transverse, pointed arches and a presbytery covered by a cross vault. On the bottom wall, a shell-like fluting niche hosts the simulacrum of the Saint to whom the church is dedicated. The original plan has conserved the holy-water font on the left of the entranceway. The stoup is supported by a stem decorated with interlace motifs and mouldings, supported by a truncatedpyramid basis, tapering in a thin neck and then widening up to the insertion of the basin. The exterior of this latter presents a decoration recalling compositions with egg-and-dart moulding, of most ancient tradition. Inside the stoup is a high-relief of four big fish, randomly scattered. th A barrel-vaulted side chapel was then added to the original building structure (17 C.). It guards the statues that are carried in procession on the occasion of Holy Week rites.
Indeed, this oratory dedicated to the Archangel was built on the initiative of the 'Confraternita del Sacro Monte della SS.Vergine della Pietà'. The Brotherhood was raised to the status of Archconfraternity by a Papal Brief th of 16 November, 1616. Indeed, charitable corporal works and spiritual mercy have always been its inspiring principles, put into practice in the assistance to people sentenced to death and in the organization of Holy Week rites as well. In Holy Week, the oratory becomes the focus of the religious life of the town, as this is the meeting place of the processions, calling the faithful to the mysteries of Jesus's passion. Carrying out rituals unchanged throughout the centuries, the brothers wear their characteristic garments of Spanish origin and accompany the congregation down the streets of the old town, in an evocative event inviting to meditation and prayer. Children, youngsters and adults take part to processions wearing a white, calf-length tunic of cloth, tightened by a cord at their waist. Their face is concealed by a hood called 'visiera'. Due to their particular outfit, they are called 'Baballotti' in Sardinian (in the Campidanese variant, where it means 'small animal, or insect'). In contrast, the Archconfraternity members are called 'Germani' - term of plain Spanish derivation, from 'hermano', i.e.'brother'). Their shirt is adorned by black velvet ribbons and volants on the shoulders, around the neck, along the front opening and at the end of the sleeves. A starched ankle-length skirt - tied on the hips by a white silk band ending in a rosette - and a pointed hood complete their attire.