The Church was consecrated in 1221 by Pope Honorius III: on the wall of the left nave, the inscription commemorating the event is visible. It was dedicated to Saint Anastasius, like the previous one, and only in 1370 was it called "of Saints Anastasius and Vincent", when the relics of the latter, a Spanish martyr, arrived at the monastery of the Three Fountains.

The church was built according to the Cistercian stylistic rules, which required features of sobriety and austerity. However, this did not detract from the pursuit of beauty and balance, always present in the "Bernardine" style, that is, "Romanesque-Burgundian"; so much so that it represents one of the most interesting monuments of Roman medieval architecture in transition.

The structure of the church opens to the view with a tetrastyle portico composed of oriental marble columns and Ionic capitals and a roof that does not overhang on the sides, but develops along the entire length of the three naves. Inside, the plan of the church develops in the form of a Latin cross, with a square apse and side chapels and is made up of three naves; the largest of which, the central one, is made of brick and was intended to have a vaulted ceiling, but the collapse of the walls forced the completion of the work with simple exposed trusses.

The side naves, on the other hand, are covered with ribbed vaults supported by nine pillars and open onto the main nave through round arches. Finally, pointed vaults constitute the roof of the four chapels of the pseudo-transept. Light spreads into the church through single-lancet windows with double internal and external splays, decorated with modern stained glass windows and from the front of the central nave through a rose window and five single-lancet windows.

There are fresco decorations both on the side pillars, where figures of the Apostles have been painted, and on the back pillars of the central nave, where "the baptism in the Jordan" and "Christ and Mary Magdalene" have been depicted.