Time was when this ornate gem of a palace contained one of Rome's most charming little museums; but staffing cuts and general neglect by authorities (the long-suffering staff-survivors couldn't be nicer) have reduced it to four dusty hard-to-find rooms - no longer bewitching enough to make you forget that most of the contents are second-rate 17th-century leftovers. The Italian Consigilio di Stato - a kind of appeals court - now sprawls through the palace, which was built in 1540, and acquired by Cardinal Bernardino Spada in 1632.
Spada was an avid art collector, and very fond of having his portrait painted, as demonstrated in Room 1 of the gallery. The walls of the four small upstairs saloni, entered by the back stairs, are crammed and old-style, but notes (in English) in each room help you to make sense of them all. There are some big names here: Domenichino, Guercino and Guido Reni - see his San Girolamo and Slave of Ripa Grande - plus the father-daughter Gentileschi duo, Orazio and Artemisia. Her Madonna Nursing the Infant Jesus gives a rare female view of the subject. Cleopatra gets odd treatment: in Room 2, she is adorned with a wacky hat by Lavinia Fontana, while in Room 3, Francesco Trevisani pictures the Egyptian queen as a blonde at an intimate dinner with Mark Anthony.
The main attraction, however, is the Borromini perspective, which shows that the manic-depressive architect had a sense, if not of humour, at least of irony. If you're lucky to get there at the right moment (there appears to be no timetable) you'll be taken to a courtyard and misled into believing a 9m-long (30ft) colonnade is much longer by perspective trickery. In theory, an art historian conducts guided tours around the impressive art works in the Consiglio di Stato spaces on the first Sunday of each month; phone for details and to book.