 All that is left of these two side aisles, after the late 16th-century rebuilding, are the two side chapels of the basilica church.In the Synod of 565, the church is first referred to by the title of Susanna; the church has been dedicated to her veneration ever since.In the "acta", Susanna is martyred with her family when the girl refuses to marry the son of Emperor Diocletian; the occasion of Susanna's martyrdom is a literary trope that is familiar in other "passions" of virgins in the Roman Martyrology

Pope Sergius I restored it at the end of the 7th century, but Pope Leo III, the fourth pope who had been pastor of this church, rebuilt it from the ground in 796, adding the great apse and conserving the relics of the saints in the crypt.