[1] The first castle was built in the 13th century at the north-western corner of the fortified village of Romano.

It had a quadrangular plan with an internal courtyard and was surrounded by a large moat connected to the town's walls.

Bartolomeo Colleoni, who became lord of Romano in 1448 as supreme commander of the Venice troops, transformed the southern wing of the castle and created a large reception room (the Sala Grande) on the first floor of the western wing.

[2] The walls of the primitive castle are partly built with river pebbles arranged in a herringbone pattern or mixed with brick courses.

[3] Today, the Rocca is the seat of the municipal library and the Parco del Serio.