From the 11th to the 16th century, other fortifications were added and the complex became a valuable outpost of the Duchy of Milan.
In the second half of the twelfth century Frederick Barbarossa expanded the fortress and used it as one of his residences.
In the fourteenth century Barnabò Visconti, lord of Milan, took the fortress from the Torriani and rebuilt it in 1370.
It is in this new fourteenth-century guise that it has come to us.
During the Spanish domination of Lombardy (16th and 17th centuries) the fortress was used as a prison, and then fell into a period of neglect.
Since 1805, the manor has been used as a quarry for already squared materials for the civic arena of Milan and some Monza appurtenances of the royal villa.
Only in the middle of the century did the owner Giovanna Borghi suspend dismantling at the Trezzo castle, restoring the climb to the tower.
In 1891 the fortress was purchased by Cristoforo Benigno Crespi, owner of the Crespi d'Adda cotton mill.
The castle is currently owned by the Municipality of Trezzo sull'Adda.