Castello Colleoni, Medieval castle in Solza, Italy.

Castello Colleoni stands on a slight slope near the Adda and the church of San Giorgio in Solza. Its quadrilateral plan no longer keeps its 14th-century form: the massive tower shows no sign of rebuilding, the north wall is thinner, and the scarped wall bases are the only trace of the former moat. Farm use left visible layers in the masonry.

The castle is documented from 1404, when Guelph and Ghibelline families clashed there, as recorded by chronicler Castello Castelli. It was attacked repeatedly but never taken. After the 1428 Peace of Ferrara brought Bergamo under Venice, Solza lost strategic value. Bartolomeo Colleoni, born in 1395, left the castle to the Luogo Pio Colleoni, founded on 19 February 1466.

The castle's name and identity are tied to Bartolomeo Colleoni, who was born here in 1395. In 1466 he founded the Luogo Pio Colleoni in Bergamo, to which he left the castle; the townspeople of Solza then became tenants paying 140 lire a year, and disputes over rent and repairs lasted into the 17th century. A 1491 deed records the condottiero's personal coat of arms placed on the walls.

To visit, you need to contact the Compagnia D'Arme del Carro in advance to arrange a tour. The site now serves cultural and educational purposes, so checking ahead helps ensure access at the right time.

After major restoration work in 2005, the castle was converted into a multipurpose center housing the municipal library, a children's play area, and a research center. This adaptation shows how a medieval structure found a new role serving the community.