The Walls of Viterbo, in Viterbo, Italy, developed over centuries, but much of these circumscribing, defensive medieval structures still exists, and their entrance gates, often modernized, still limit the access at certain sites.
While it is expected that the Ancient Etruscan or Roman town at this site also had defensive walls, this has not been conclusively determined. Some stone blocks near the Palazzo Farnese near the town center are assigned to an ancient construction, perhaps a wall. The main walls seen now were erected during the turbulent 11th and 13th centuries to encompass three hills, provided room for urban expansion. The era of its construction was beset by both internicine Guelphs and Ghibellines warfare, as well as foreign army sieges.
In Cesare Pinzi's 1911 guide to the principal monuments of Viterbo, he states a timeline:[1]
The walls are punctured by a number of gates, including now remaining: