Towards the 11th century Cavriana became one of the properties of Canossa and it is in this period that the first fortification was probably built. Subsequently to the Canossa the ownership of the village passes to the free Municipality of Mantua that, to defend the boundaries from the growing power of the Municipality of Verona, grants it to the family of the Riva with defensive tasks but, in the second half of the XIII century, they are supplanted by the emergent family of the Bonacolsi, who in turn, in 1328, were replaced by the Gonzagas with the election to Imperial Vicar of Luigi Gonzaga by the Emperor Ludwig IV the Bavaro. With the increase in danger due to the neighboring Visconti, the castle is reinforced with high walls that surround the entire village, while the fortress has at that time four towers at the corners; in the second half of the 14th century clashes with the Visconti are frequent and in 1383 he moved to Cavriana Francesco I Gonzaga to escape the plague and died here in 1407.
Between 1458 and 1461 the fortress was strengthened and modified to a design by Giovanni da Padova to adapt to new war techniques and the advent of cannons, it is also surrounded by a system of ditches. In 1501 Francesco II Gonzaga, at the time military commander in the pay of the Serenissima, armed the fortress of artillery.
In the first decades of the 17th century the Rocca Castello di Cavriana appears to be the largest of the state, is then attacked and occupied with partial demolition, so that in a census of the defensive structures of 1650 the castle is decayed. In 1708 the Gonzagas fall and the Austrians are not interested in rebuilding the fortification, so much so that in 1771 they ordered the demolition.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.