Covered with dense woods, Mount Tifata was dedicated to Diana the huntress goddess, Artemis of the Greeks, who introduced its cult among the coastal cities first and then in the hinterlands as their influence among indigenous peoples increased. The Etruscans then extended their dominion in the area and erected the federal sanctuary of the Etruscan cities in Campania, dedicating it to Diana Tifatina.
The perimeter of that temple, as discovered from archaeological investigations carried out in the 19th century, was used in the Lombard period for the construction of a church dedicated to St. Michael the Archangel, to whom the Lombards had become very devoted after their conversion to Christianity in the 6th century AD.
That church, was the first nucleus of an important monastic complex of which parts coming down to us represent one of the oldest testimonies of sacred architecture in the South, whose value is increased by the state of excellent conservation of the important cycle of Byzantine frescos.
The ancient abbey, which is a minor basilica, stands on the western slope of Mount Tifata, in the territory of St. Angelo in Formis, fraction of the Municipality of Capua, from which it is exactly as far as St. Mary Capua Vetere, the most ancient Capua. And from the large square in front of the church opens a magnificent view of today's Capua.
The first document on the church dates back to the first half of the 10th century, when the bishop of Capua of that time, Pietro I, granted its possession to the Benedictine monks of Montecassino of what was literally referred to as the church of St. Michael Archangelad arcum Dianae, denomination present in every contemporary document, with a clear reference to the pre-existing temple. Later, instead of the arch, the formulas ad Formas and then Formis appeared, whose etymology has lent itself to various interpretations, still conflicting. Some found a theological meaning, identifying it with the adjective "spiritual", and some on the other hand, has traced everything back to the "form", that is an aqueduct of which there are several traces in the area.
From a historical point of view, in 943 the controversial bishop of Capua Sicone took possession of the church again, ousting the monks, who appealed to Pope Marino II, who granted them the restitution. In 1065 the prince of Capua and count of Aversa, the Norman Riccardo Drengot, a violent man who wanted to make amends for his sins, obtained the church to build a monastery, to which he later handed over many other properties. In 1072 he then decided to transfer all the buildings and benefits connected to the powerful Abbot of Montecassino Desiderio, future Pope Victor III from 1086.
