In the fourteenth century Marostica took on the appearance of a medieval fortified city, thanks to the Scaglieri family, the lords of Verona, who replaced the previous blank spaces of the fortifications on tops of the hills, which appeared in the Roman age in Ezzelino. This project aimed to transform Marostica into a military stronghold to enable the political control of the area. We owe to Cangrande, Mastino and Cansignorio della Scala the "oppidum Marosticae", still an object of study for its rigorous and prudent community system. There are two castles, one on the plain and one on the top of the Pausolino, joined by a massive wall, which surrounds the hill and the terrain below.

Inside the walls there are the typical elements of a fortified city: a "big field" for meetings, parties and tournaments; a castle yard, a trade centre and a customs house; shops of arts and crafts, a part of the Marostican canal to ensure water supply; agricultural districts; residential buildings, stables, and shelters for the residents of the county in case of danger. The Caste'o da basso has two gates and four shielded turrets, as well as the bastion of Cangrande, a tower of 44 m. It seems to have been influenced by the model of a Lombardy town hall. The Caste'o de sora, partially destroyed by Venetian army at the time of the League of Cambrai (1510), is today reduced to ruins.