In 1949 archaeological investigations carried out in the square in front of the church brought to light some structures of the early Christian basilica dating back to the decades between the fifth and sixth centuries, and in particular some portions of the apse.

In 1534 a part of the monastery's structures was handed over to Gerolamo Emiliani, who assigned them to the assistance of orphans, while a few years later, in 1542, the church passed to the Franciscans.

[5] Above the atrium of the portico, three windows overlook the internal space of the counter-façade which houses the organ.The eighteenth-century facade, not completed, is very simple and has a small portico with three lights and ends with an unplastered tympanum, tripartite by pilasters.The interior, according to the dictates of the Council of Trent, has a single hall covered by a barrel vault with six side chapels, three on each side.

Due to the modalities of his martyrdom, through numerous arrows the saint was highly revered in the past as a protector against the plague.

During some archaeological investigations carried out inside the chapel in 1875, the original granite sarcophagus was found in which the body of Saint Syrus was placed in the 4th century.