The beautiful church was probably built in the ninth century and originally dedicated to the Holy Trinity. Located above the Grotto of San Michele, she emphasized, thanks to her position, a sort of celestial hierarchy, in the obvious attempt to combat the spread of the heresy of Cerito of Antioch, who wanted the Angels creators of the world.
The imposing building is built in a warm sandstone and blends styles and themes of Byzantine architecture such as the two domes, one with a circular base, the other with an elliptical base, connected by barrel vault, with construction elements typical of Norman architecture. The church has unequivocal signs of tampering suffered over the centuries, as the opening of multiple entrances on the long sides of the body of the building. The most evident element of alteration is the demolition with the closing of the apse, with the opening of a window by the Guevara dukes, who took over the entire abbey complex in the 16th century, transforming it into a noble residence. This intervention was linked to the need to create a direct link between the apartments of the dukes and the church, so that the nobles could attend the functions without leaving the house and thus mingle with the plebs. All this led to the overturning of the church’s interior layout, including the displacement of the altar.
Following the restoration works carried out in the 80s of the last century, the original internal distribution was restored and the spaces were enriched by a pulpit, an altar with seat and a cross, assembled with decorative elements and stone materials found in the outdoor area overlooking the same building. On the side of the Church you can visit some rooms of the monastery of the former Abbey: these are probably rooms that were intended for the hospitality of pilgrims and travelers and are characterized by the presence of vaults; In them it is also possible to see the remains of the demolished apse of the Church Dell'Annunziata.