Charles VIII founded it in 1493, under a Latin title that called it the Trinity on the Pincio. Work on the first part probably began at the start of the sixteenth century and went on for most of it: that first core is in full Gothic style, designed by Annibale Lippi and Gregorio Caronica and built with stone brought from Narbonne. The name we use today comes from a mistake: it was originally the Trinity of the Mount, in the singular, after the hill it stands on, and the plural comes from a wrong translation of the Latin that only came into use in the nineteenth century. The church has always been under the protection of the crown of France, so much so that the northern part of the square below was long called the French side; mass is still said here in French as well.
What to see
The façade has a single order of pilasters and two twin bell towers with octagonal cupolas: on one there is a clock, on the other a sundial, said to give the hour of Rome and the hour of Paris. Inside, a single nave with six side chapels. The vault over the crossing, among the first parts to be built, is in late French Gothic with interlaced ribs: the only example of that style in Rome. In the chapels are the Deposition painted by Daniele da Volterra in 1541 and the cycle of the chapel of Lucrezia della Rovere, where, according to Vasari, the master drew all the cartoons but the painting is largely by his pupils. Two of the cycles still have no known author: one is by an artist of Raphaelesque training who perhaps worked on the Vatican loggias, the other probably by an Umbrian close to Pinturicchio. The church originally held an altarpiece by Jean-Auguste-Dominique Ingres as well.
Visiting
The stair in front of the door is not the famous one. When Sixtus V consecrated the church, in 1585, he charged Domenico Fontana with opening a road to link the Pincio with Santa Maria Maggiore, and that road took its name from the pope himself; the cuttings, however, left a huge drop in front of the main entrance, and Fontana answered it with the monumental two-ramp stair that still leads up to the door. On the terrace in front, at the end of the eighteenth century, Pius VI had the Sallustian obelisk raised: it is not Egyptian but Roman, cut in imitation of those, and it was the second to last of the great obelisks set up in papal Rome. In the convent next door are the perspective gallery frescoed by Andrea Pozzo, the Room of the Ruins painted by the Frenchman Charles-Louis Clérisseau with a sensibility already Romantic — the artist ended his days in St Petersburg, at the court of the tsars — and the Mater admirabilis, frescoed in the middle of the nineteenth century by Pauline Perdrau.
Our editors' tip
Look at the two bell towers one after the other, and then think of what lies behind the wall. In a corridor of the convent Emanuel Maignan built a reflecting sundial, and across the vault run several sets of lines told apart by colour: the Italian hour, the French hour and others besides. In the same place are two anamorphic paintings of 1642, Maignan's St Francis of Paola and the St John writing the Apocalypse begun by Jean François Niceron and finished by Maignan: images that come together only from one exact point and from any other stay a long smear. A house that measures time twice over and paints its figures to be seen from one side only says more than any plaque about what it means to live between two countries.