 Catinat was completely surprised, for he had counted upon Venetian neutrality, and when in the search for a passage over the lower Adige, Eugene's army spread to Legnago and beyond, he made the mistake of supposing that the Austrians intended to invade the Spanish possessions south of the Po River.His first dispositions had, of course, been for the defence of the Rivoli approaches, but he now thinned out his line until it reached to the Po.After five weeks of cautious manoeuvring on both sides, Eugene found an unguarded spot about 10 km southeast of Legnago near the town of Castagnaro.