It rises at the northern vertex of the rough triangle traced by the town walls, built by Emperor Aurelian in the 3rd century, in the area of Trastevere and up through the Janiculum.

The most recent hypotheses take into account the possibility that the name comes from the proximity to a monument of the age of Septimius Severus: maybe it was an arch of the aqueduct bringing water to the thermal baths dedicated to the Emperor; maybe the entrance of the Horti Getae, the gardens owned by the Emperor's son Publius Septimius Geta, the brother of Caracalla and co-Emperor for few months; maybe a rear gate giving access to the quarter of Trastevere, within walls that had no military importance at that time.

During the Middle Ages there was a proliferation of legends: according to one of them, Augustus, before becoming Emperor, had raised seven hymns while making a pilgrimage to the Temple of Janus (septem Iano laudes).

The street and the gate are mentioned in some documents dating back to the end of the 14th century, disposing to keep both of them clean and free of debris from the flood of the river and to throw no garbage, so that the road was adequate to its name and function.

The last renovation, carried out by Pope Pius VI in 1798, maintained a military aspect - included with the guelph battlements - scarcely justifiable for a gate fully integrated into a city quarter.