Porta Tiburtina

Porta Tiburtina or Porta San Lorenzo is a gateway in the Aurelian Walls of Rome, through which the Via Tiburtina exited the city. Initially, it was only a monumental archway built in the Augustan age (5 BC) to allow the passage of a group of aqueducts (Aqua Marcia, Tepula, Iulia) above Via Tiburtina. Between 270 and 275, the Walls incorporated the arch.

When Emperor Honorius restored and reinforced the Walls (401-402), a new entrance was added in front of the older one, later destroyed by Pius IX in 1869. In this way, the whole structure has a double architectural aspect: the Roman republican one towards the inside and the external one with merlons and towers. Furthermore, the base of the outer door is about a meter and a half higher than that of the Augustan arch and has a not-symmetrical opening.

The arch erected by Augustus, which now forms the inner side of the door and is located at a level somewhat lower than today's street level, is made entirely of travertine. It is in excellent condition with Tuscan pilasters and keystones decorated with bucrania.

The attic, crossed by three aqueducts, bears three inscriptions. The upper one, which corresponds with the Aqua Iulia canal, dates back to the year of construction of the arch. In the center, on the Aqua Tepula conduit, is an inscription dating back to the restoration of Caracalla in 212. On the lower channel, that of the Aqua Marcia bears an inscription celebrating the restoration ordered by Titus in 79. On the other side is the Honorian inscription commemorating the enlargement of the walls and the name of Flavius Macrobius Longinianus, prefect of Rome in 402, as the curator of the work.