San Carlo alle Quattro Fontane, also known as San Carlino, the Church in Rome, built by the architect Francesco Borromini. It is considered a masterpiece of Baroque architecture and is part of a complex of monastic buildings on the Quirinal hill, which was built for the Spanish Catholic order of Trinitarians. Barberini was commissioned to build the Church in 1634 from cardinal Francesco Barberini, whose residence was across the street. However, the financial support of the cardinal was short-lived, and during the construction of the Church workers all the time faced with lack of funds. Interestingly, the Church is also one of three in Rome, dedicated to Saint Charles, along with San Carlo AI Catinari and San Carlo al Corso.

First, on the Quirinal hill was built a complex of monastic buildings and the cloister, and only then, in 1638, construction began on the Church of San Carlino, which was completed in 1641. Five years later the Church was consecrated in honor of St. Carlo Borromeo. The location of the Church and monastic buildings, is located on the corner "Four Fountains (Quattro Fontane), groups of four fountains at the intersection of Strada Pia and the Strada Felice. Nearby stands the Church of Sant'andrea al Quirinale by Bernini.

Concave-convex facade of San Carlino is executed in classical style. High Corinthian columns stand on plinths and attract attention because of their trim – they divide the facade into two levels. Between the columns are smaller columns – they frame the niches, Windows, and various sculptures. Over the main entrance the figures of the cherubim surround the sculpture of Carlo Borromeo work of Antonio Raggi. On the sides are statues of saints Jean de Matha and Felix de Valois, the founders of the order of Trinitarians.

The interior of San Carlino is quite extraordinary. One of the doors inside leading to the monastery, where you can get into the crypt with several chapels. The other door leads to the chapel, known as the Barberini Chapel in which the relics of St. Elizabeth of Canori Mora.