Santo Stefano del Cacco

Santo Stefano de Pinea or more commonly Santo Stefano del Cacco is a church in Rome dedicated to Saint Stephen, located at Via di Santo Stefano del Cacco 26.
Name.
"del Cacco" may refer to the Roman deity Cacus, or more likely to a statue of the dog-headed (baboon, actually) ancient Egyptian god Thoth (from the temple of the ancient Egyptian deities Isis and Serapis, the Iseum Campense, built in 43 BC, on whose ruins the church was originally built and twelve columns from which were re-used in the church's nave), misunderstood as a monkey or "Macaco" (later corrupted to Cacco.
History.
Its construction date is uncertain, though it is assumed to have been in the reign of pope Hadrian I (772–795). It was definitely in existence at the time of pope St. Paschal I (817-824), who added an apsidal mosaic (lost in the 1607 rebuild) of himself with a model of the church. Under Paschal II (1099–1118) the painters Gregorius and Petrolinus were employed to work on the church's apsidal decoration. A new bell-tower (not visible from the street) was built in 1160, and still survives.
In 1563 it was assigned by pope Pius IV (1559–1565) to the Sylvestrine Fathers, by whom it is still run, and they soon carried out a minor restoration. Other restorations and renovations occurred in 1607 (gutting the apse), c.1640 (giving the church its current baroque appearance, with a simple 2 storey façade, probably by Antonio Canziani), 1725, 1857 and 2007 (interior). In 1940, the church was threatened with demolition by the expansion of the central police-station in the neighbouring former monastery of Santa Marta, though this was averted. The interior of the church is at present undergoing another comprehensive restoration.
Paolo Maruscelli (1594–1649) designed the church's travertine portal, flanked by pilasters and surmounted by a triangular pediment, and the plate above it reads: D. STEPH. PROT. CONG. MONAC. / SILVESTRINORVM. The façade's second order includes a window crowned with a segmented pediment and flanking pilasters, and right at the top is a triangular pediment with a small window, a rare feature in Roman churches.