Traditionally ascribed to the architect Francesco Borromini (1599-1667), the Spada Chapel (first on the right) is separated from the nave not by the traditional balustrade but by a pair of genuflecting marble angels, who hold between them a long cloth carved from red jasper. The angels, the work of Antonio Giorgetti (1635-69), seem to block access to the chapel, but the wings of the angel on the right are made of wood, not marble, and can be moved aside (by means of a hinge).
Two members of the Spada family recline on either side of the chapel, one awake and one asleep. The sleeping figure of Bernardino Lorenzo Spada is by Ercole Ferrata (1610-86), while Giovanni Spada is the work of Cosimo Fancelli (c. 1620-88).
Spada is the Italian word for sword and three swords make up the family's coat of arms. Images of swords make up some of the ostentatiously ornate marble decoration of the walls of the chapel.
The floor of the chapel is a beautiful example of pietra dura work, which incorporates a myriad of flowers in its design.