It is believed that already at the beginning of the twelfth century, there was a fortified structure here, later evolved into a traditional Vercelli castle structure typical of the plains. Today traces of the fourteenth-century renovations and a later one are still visible. The oldest section, a castle-fortress with an entrance tower and town walls, was transformed into a fortified building with four corner towers and the superelevation of the town walls and entrance tower. Today, in addition to the latter, two corner towers are still standing, one of which is octagonal.

Between the twelfth and thirteenth centuries, Collobiano was one of the most important Guelph strongholds in the Vercelli area and, because of its strategic position, between the sixteenth and seventeenth century, it was involved in the wars between the Savoy, France, and Spain. Until 1704, it was used for military purposes, but effective from 1713, it took on an agricultural role.