Archaeological and topographic research has allowed to spot the remains of three walls around Todi. In different ages, they defined the urban area and protected the town borders: the first walls, commonly called “Etruscan” and almost disappeared, would date back to the 3rd century B.C. The second “Roman” ones would date back to the 1st century B.C., when the town gained the status of municipium. The third and last walls, the Medieval ones, date back to the 13th century and are the most extended ones in terms of urban space, up to the present day.
The third and last walls, which building works started in 1244, include: Porta Perugina (a steady Medieval bastion structured on two levels), Porta Romana (built in the 16th century as wished by Pope Gregory XIII, consisting of a single arch made of white and red blocks, the most modern gate among the still existing ones), Porta Amerina (also called Fratta, built in the 14th century and again structured on two levels) and Porta Orvietana (an underground ruin by now, because of landslides).
Each of these gates, placed on Todi main road systems, used to be named after the town it would overlook and, in the Middle Ages, it was a copy of the previous Roman gate.
Porta Libera, as well, belongs to the Middle Ages and is located nearby Parco della Rocca.
The second walls include: Porta Aurea (stone made and currently well preserved. It must have been the Roman outpost of the nearby Medieval Porta Fratta), Porta Catena (also called of St. Antonio, currently in via Matteotti which Ulpiano district stretches from) Porta di Santa Prassede (nearby Borgo Nuovo in the North of the town).
Only Porta Marzia, opening out onto via Roma, remains of the most ancient walls. In the historical texts, there is evidence of other Todi monumental gates, currently disappeared, such as Porta della Valle, Porta Liminaria, Porta Bonella and Porta di St. Giorgio.