This unusual church was transformed by the Jesuits from 15th century Palazzo San Severino, the one-time residence of the Prince of Salerno, in the late 1700s. Its striking facade, a rare example of bugnato a punta di diamante (ashlar work), was preserved from the palazzo's original facade, while a baroque portal was created to encompass the original Renaissance portal. The church's interior is opulent and features stuccoes, frescoes, and marble decorations by some of Naples's best artists from the 16th century to the beginning of the 19th. Among the masterpieces are the impressive fresco by Francesco Solimena, called the Expulsion of Eliodorus from the Temple, and the rich decorations in the left transept, including a beautiful altar and statues of Jeremiah and David by Cosimo Fanzago. The oratory is usually closed, but you can request entry from the custode (keeper) of the Liceo at number 1 of Piazza del Gesù.
On the piazza outside the church, you'll find one of Naples's several baroque spires, the Guglia dell'Immacolata, a tall column of statues and reliefs. Typically Neapolitan, this kind of religious monument is modeled after processional objects -- part float, part conglomeration of statues and figures -- built for religious celebrations from baroque times until the 1950s. This particular spire was created in 1750 by Matteo Bottighero and Francesco Pagano to celebrate one of the major points of the Jesuits' teachings; it depicts Jesuit saints and the story of Mary.