Town in Alessandria province, Piedmont region, 12 mi E of Alessandria, N Italy. Settled by Ligurians, it was made a Roman colony in 148 b.c. and was a Guelph fortress during the Middle Ages. It was razed by Frederick I Barbarossa in 1155 and was taken by the Visconti in 1347. After the Battle of Marengo the town's citadel was dismantled by Napoleon in 1801.