The Castellazzo, il castlass in Piedmontese, is what remains of the medieval fortification on the morainic hill that overlooks Caluso. It was not a castle in the full sense, like the one at nearby Mazzè, but a military structure put up to control the roads that ran at the foot of the hill towards Ivrea and towards Vische, in the direction of the Vercelli country. A deed of 1257 calls it castellacium; a document from the end of that century already calls it castrum.
What to see
What survives of the fortification is a long wall of brick and stone running along the ridge, with one corner pier still standing and the grass climbing right up to the masonry. A little lower down, to the south, lie the ruins of the church of San Calocero, which belonged to the same fortified system. The position explains more than any description could: from up there you keep an eye on the plain and control who passes, and it is the same reason the Romans made Caluso a closed oppidum guarding the road to Eporedia, today's Ivrea.
Visiting
In 1316 Filippo d'Acaja took over the fief of Caluso from the Biandrate, and eight years later made it a stronghold of the Guelph party in the Canavese: the castellazzo was strengthened enough to house a garrison of 200 soldiers, brought in specially from Ivrea. In the wars between Guelphs and Ghibellines, the ones the fourteenth-century chronicler Pietro Azario recounts in his De Bello Canepiciano, Caluso was a thorn in the side of Giovanni II Palaeologus, marquis of Montferrat, who tried more than once by sending in his mercenaries and was always driven back. In June 1349 he finally managed to enter the town and lay siege to the stronghold. In 1376 the fief passed to the Valperga di Rivara, who from then on called themselves Valperga di Caluso and held it until 1537, when the Spanish arrived: general Cesare Maggi dismantled the castellazzo for fear it would fall into French hands, and nobody has rebuilt it since.
Our editors' tip
The hill reached the twentieth century as a ruin under brambles. The municipality bought the remains in 1951 from the Mattirolo, heirs of the Spurgazzi, and for years nothing happened, until in 1980 the site was cleared and the western wall consolidated. Go towards evening, when the low sun rakes the brick and sets it alight: that is the moment you grasp how long that wall was. And walk the whole ridge instead of stopping at the first stretch, because the church of San Calocero and the wall stand on the same height and, seen together, tell a single story: a military post and the church that belonged to it.