The walls, already existing in Roman times, are one of the representive elements of the city of Rieti. They underwent a first enlargement in the early Middle Ages. After the year 1000, and particularly during the communal age, Rieti experienced a period of richness, interrupted by the terrible black plague of 1348. It is to this phase that the vestiges that include the current historic town center belong.
The western and southern sides of the city are naturally protected by the course of the Velino River. The current extension of the Walls therefore stretches along the northern and eastern sides. The height of the fortifications is variable. The walls are irregular, made of pebbles and stones bound with lime mortar while the regular hangings (mounted on rows where square and rectangular blocks are arranged) are above all in the angular parts and near the doors.