The crypt is situated below the presbytery of the archpriest church of Brentonico. It is the historic and artistic architectural testimony to this site's dignity. It is an austere romanic stone environment with arches, vaults and cross vaults supported by a double line of quadrangular columns with capitals. One of these columns is cylindrical with stylized crosses and tendrils engraved on it.
Once the church was decorated with frescoes, two of them are still visible, one is positioned on a resin, on a side altar of the upper church, and represents the Crucifixion. It was built between the 8th and the 10th century. It is the only medieval church in Trento which is still intact. It was dedicated to St. John the Baptists, and until the 17th century it had a baptistery. To reach the crypt there are two symmetrical staircases, one of which outside the church.
(source: Guida all'Altopiano di Brentonico, A. Bertolli, ed. Curcu & Genovese, 2013).