River Olona

The river Olona played an important role in the history of local populations, forming an artery of communication between the Po valley plains and the Alpine regions. Towards the end of the Roman Empire, the Olona area increased in importance, because it lay inside the defensive network that the Romans established south of the Alps. Of particular significance in this context was Sibrium (Castelseprio), situated at the centre of a system of observation towers that the Romans built along the "limes" (frontier) in order to guard the area and relay information. After the fall of the Empire, the age of Communes was hallmarked by interminable conflict that eventually caused the destruction of Castelseprio and the start of Milan's domination. It also left many castles built along the river Olona. The monumental settlement of Castiglione Olona is of particular interest: it reflects the great personality and ambition of Cardinal Branda Castiglioni.