The Testaccio area, not included in the most ancient walls of Rome, was englobed in the so-called Aurelian Walls, wanted by the emperor Aurelian and completed by his successor Probo between 271 and 279 AD. This circuit, a little shorter than 19 kilometres, was built in order to deal with the defensive exigencies of the city, capital of a wide empire threatened by Barbarians. Besides strategical criteria, the need for an inexpensive and rapid execution determined the choise of the route. Thus some pre-existing structures were enclosed into the new walls; among them the Pyramid of Cestius, the monumental tomb of the Augustan Age, that could have been a factor of risk in the case of a siege. In the Testaccio zone, the Aurelian Walls, today paricularly well preserved along Via del Foro Boario, considerably changed the relation between the city and the river port, probably contributing to the abandonment of the dump of amphoras that made up the modern Monte dei Cocci and that remains a record of the consistency of business between the 1st and the 3rd century AD.

The Aurelian Walls were built in brick-faced concrete (opus latericium), originally about 6.5 metres high and 3.5 large, and provided with an open wall walk protected by merlons and square towers every 30 metres. Afterwards the walls underwent restoration and settlement works until the modern age, since, until 1870, when the Kingdom of Italy took the city away from the Popes, they still represented the main fortification of Rome.
The walls elevation undertaken between 401 and 403 AD under the emperor Honorius has to be paricularly reminded because of its strong impact, while important works, defined by the use of small blocks of tufo and the presence of big merlons, were made in the 15th century AD in the section between Porta Ostiense and the Tiber.


(L. D’Alessandro)