This description by Marin Sanudo summarizes the fortification structure of 1483 at the moment when the city reached its peak followed then by its inexorable decline. 

Castle and “land”, joined by walls, are the final product of a long evolution.

News about fortification works are found in a document of 1189, which attests that thirty years earlier the peasants of the neighbouring villages were obliged to dig moats and build walls (“foedere fossatum et aedificare murum”).

In 1184 there is again referral to “muro et foveis”, walls and moats, most probably attributed to the most external walls of the castle, called “zirone” or “girone” (ring) walls .

At the beginning of the 13th century the structure of the city is already organized, with the old castle on the hilltop and the village below. The fortified residences of the most important “consortes” (members of the municipal government) are situated on the “castro” (open area) around the Castelvecchio. 
At the beginning of the 14th century the fortifications of the village and those between the village and the castle are made of walls alternated with thorny hedges and glacis.

Under the Scaligeri family, between 1330 and 1334, necessary and expensive restorations and fortification extensions are carried out. A good part of the work is assigned to the supervisor and engineer Coneglan Caronello, thanks to him the surrounding walls of the village and those between the village and the castle are built.

He also completes the podesta palace, fortifies the Castelvecchio with an internal wall and four corner towers and oversees excavation of the “Refosso” (ditch) along the southern perimeter of the village.
From 1339 to 1381, under the Serenissima Venetian Republic, towers and guard walkways are completed and the bastions of Borgovecchio are built, in the direction of Friuli.

Between 1384 and 1389, under the Carraresi rule, the area of Monticano Gate is restructured, with the building of the “Rocha nova”, and the western village walls are fortified.

After the siege of the Hungarians, who were pushed back in 1412, and the Venetian conquest of the Friuli region in 1420, the structures of the walled city, losing their purpose, are left to perish.