The main altar forms a single body with the ogival-shaped niche above it. The structure was born in the centuries ago as the only project designed to immediately enhance the devotional complex of the place. The external covering is double sloping made of typical chiancarelle of the territory, while the internal arch is pointed arch. The artificial cavity thus composed houses the altar and the seats, also in stone, for the altar servers the devotional liturgical function.
The construction of this house-shaped niche inside the cave, therefore in any case a place already protected in itself, shows a strong sacralization of the place, a "house within a house" is equivalent to saying "Sacralize the Sacred".
The front wall in direct contact with the rock has a fresco decoration with the representation of the Crucifixion of Christ. The fresco is spread in a single layer of plaster and was created simultaneously by two artists from Puglia. The different hands can be seen both from the conceptual point of view and from the way in which the content is represented. This fresco dates back to around the 14th century in the middle of the Angevin period.