The castle's history can only be pieced together from scattered documents. The first is from 1145 and names the Da Castello as owners of a fortified residence; then, between the thirteenth and fourteenth centuries, the Torriani and the Visconti appear. On 6 August 1329 a diploma of Louis the Bavarian, issued at Pavia, confirms possession of the lands to Ottorino Visconti, but when the Statutes of the Community of Castelletto were drawn up in the fourteenth century the rights over the territory were recognised only to the emperor. A Milanese chronicler of the same century calls it a bulwark defending Milanese territory.
What to see
The oldest evidence dates from the Visconti period. The plan was quadrilateral, with four corner towers: two on the north-western side, two towards the river, and the latter are badly damaged today. The masonry, closely studied, was originally of river cobbles, later reinforced with squared stone and adapted more than once, yet the original defensive purpose can still be read. On the main front is the coat of arms of the Visconti d'Aragona: the second name was added in 1471, granted by king Ferdinand of Sicily.
Visiting
Inside is a hall of coats of arms, decorated with the Visconti serpent and the imperial eagle, and with the arms of the women of the Perrone di San Martino and Visconti Ornavasso families. By the seventeenth century the castle had become a residence, and some reports of that period go so far as to state that there had never been a castle at all: it had simply vanished from everyone's memory. Today it is an old country residence.
Our editors' tip
The castle ended up in literature: it was one of the sources of inspiration for Tommaso Grossi's historical novel Marco Visconti. And the river went on mattering afterwards: in 1748 the territory passed to the House of Savoy, then to the French and back again, and in 1859 Giuseppe Garibaldi used the boats of Castelletto to cross into Lombardy.