Spoleto, like most Umbrian cities, has preserved almost intact its anti-structured profile with an interesting, ancient boundary wall still visible in various parts of the city. Studies of the remains of walls by archaeologists have made it possible to recognize different building techniques datable to a period of construction between the IV and I centuries BC. The Romans were interested in this settlement and its defense especially after Spoleto became a colonia in 241 AD and later a municipium. The entire wall was two km long, along which building techniques have been identified such as the polygonal shape and the square shape, built from long rectangular blocks of stone. You can still see pieces of the ancient wall in via dei Cecili, where a large part of the San Nicolò convent is still supported by Roman terracing; in the Piperno garden, where a Latin inscription mentions the magistrates who were responsible for restorations in the 1st century BC; and, finally, the two remaining arches at the famous Sanguinario Bridge near Piazza Garibaldi.