The gate rises close to the summit of the Janiculum hill and its first building could date back to the end of the Roman Republic, when a humble housing cluster on the right bank of the Tiber was surrounded by a little urban wall.

[2] In the vicinity, on the inner side, there were the public mills, placed close to the merge of the aqueduct called Aqua Traiana, which operated until the end of the Middle Ages.

The gate became later famous for the combats that took place in the area, in the period April – June 1849, between the military units of the Roman Republic, captained by Giuseppe Garibaldi, and the French troops intervened to protect the Papacy.

It was rebuilt to its present aspect by the architect Virginio Vespignani[3] in 1854, on commission by Pope Pius IX, and had once again a prominent role on September 20, 1870, when it was passed through by the troops of General Nino Bixio, at the same time of the one entering Porta Pia.

On the occasion of the 19th-century rehash, the following inscription was placed on the attic: (Pope Pius IX rebuilt in the year 1854, the seventh of his own pontificate, as a dwelling to host the soldiers of the garrison and as a pavilion to cash the duties in, the fortified gate built for the defense of the town at the top of Janiculum by Pope Urban VIII, destroyed by the impetus of war in 1854 – curator A.G. Torquato treasury prefect.)