The altarpiece shows the saint having been thrown to the lions in the amphitheatre, with the allegely miraculous result that they behaved like pussy cats, completed in 1667. The work was begun by Melchiorre Cafà, but he died soon after beginning it and it was compleged by Ferrata assisted by Giovanni Francesco de Rossi. The basin with emblems of the holy angels was designed by Ciro Ferri and executed by Ercole Ferrata.

(Another photo of the altarpiece here)