- Main altar
The Church construction began in 1595. It was called "dell' Ospedaletto", in memory of the hospital founded in the same place in 1514, and it is famous also as "St. Giuseppe" after the demolition of the Church of St. Giuseppe Magggiore. It has a three aisles with a transept and an apse.
Originally it was frescoed by three painters of Caravaggio's school of naturalism: Battistello Caracciolo, Massimo Stanzione and Andrea Vaccaro.
Those by Battistello Caracciolo are the only ones left, the others having been destroyed by the earthquake in 1688. There is a painting on canvas of the Death of St Joseph by Massimo Stanzione in the last right-hand chapel, while Andrea Vaccaro's painting of St. Antonio da Padova hangs in the sacristy.
The 18th-century polychrome marble main altar was designed by Giovan Battista Nauclerio and made by Giuseppe de Filippo and Giuseppe Massotti.
Against the wall there are elegant marble tombs of the princes of Piombini, works by Giacomo Colombo, sculpted between 1703 and 1704 from a design by Francesco Solimena.