On the one hand, San Carlino stands on the summit of the Quirinal, one of the seven hills on which ancient Rome once stood, and is named after four artistic fountains built on the same spot in the 16th century.

In the 16th century, Pope Sixtus V wanted to make it easier for pilgrims to find their way around Rome, and for this reason he laid out straight, perpendicular streets in the area, at the end of which he placed the ancient obelisks brought from Egypt by the Romans: Porta Pia, which is one of the ancient entrances to the city through the Aurelian wall; the obelisk next to the apse of the Basilica of Santa Maria Maggiore; the obelisk on the steps of Piazza Spagna; and the obelisk in front of the Quirinal Palace.

To complete the work, the Pope ordered the erection of four artistic fountains at the crossroads of these streets, one fountain at each corner.

This location between the four fountains is what gives the church its name and distinguishes it from other later sacred buildings that were also dedicated to Saint Charles Borromeo in Rome.

San Carlino is located just a few metres from the Quirinal Palace. Pope Gregory XIII erected this magnificent building in the 16th century as a papal summer residence.

However, with the reunification and conquest of Rome in 1870, it became the seat of the Italian State: initially, while the monarchy ruled, it was the Royal Palace. Later, after the proclamation of the Republic in 1946, it was the residence of the President of the Italian Republic, a function it still occupies today.