In the Trans-Tiberine or Trastevere area, two long sections of wall formed a V-shape and enclosed the zone between Via Portuense (at Largo Alessandro Toja – southern section), and the Lungotevere della Farnesina (at Ponte Sisto – northern section): the summit that connected these two long sections was formed by Porta Aurelia – San Pancrazio, rebuilt in the 17th century on the occasion of the construction of the Janiculum Walls or the Mura Urbaniane [built by Pope Urban VIII].
The route is about 900 metres long and almost exclusively takes in the northern section of the defensive wall from Porta Aurelia – San Pancrazio to the Tiber: the only preserved tower of the southern section is located at the start of the itinerary. The visitors’ route in the northern section does not follow an orderly course: the signposted points of interest can be reached by following the normal road network and their exact addresses are indicated to make them easier to identify.
The southern section
The new fortifications built between 1642 and 1644 by Pope Urban VIII left out of the city the part of the Aurelian Wall from the Tiber to today’s Via Aurelio Saffi where it intersected with the new 17th-century enclosure. This portion, now completely gone, was destroyed in May 1644: Porta Portuensis and a dozen towers disappeared. The next section as far as Porta Aurelia was rendered unusable, but remained largely visible until the mid-19th century: the Walls then merely served as a boundary between different properties. In 1849, what remained of the Aurelian Wall was used as a second line of defence during the fighting of the Roman Republic: the Walls, heavily damaged by bombing, were almost completely destroyed in the decades that followed.
The northern section
The northern section of the Walls of Trastevere, from Porta Aurelia – San Pancrazio to the Tiber, is still preserved for some stretches, although, as with the southern section, only a few parts retain the original appearance of the Aurelian Wall. Due to the long period of abandonment following the construction of the 17th-century walls, today it is quite difficult to recognise the defensive layout, most of which is enclosed within properties of various kinds, not always easy to access. From Porta Aurelia – San Pancrazio the walls descended along the steep slope of the Janiculum Hill in a roughly straight line to the river where, bending at right angles to the south, they reached a bridge, now gone, over which they crossed the Tiber and then went north again towards Porta Flaminia. The construction of the ramparts at the end of the 19th century caused the destruction of the last two towers, so that today the walls end with an abrupt break on the Lungotevere della Farnesina, at the Villa of the same name, for which they form a boundary wall.