223-193 BC: After this came a concerted Roman policy aimed at conquering Gallic territories south of the Alps. Rome invaded the territory of the Insubres in 223 BC, and took Clastidium, Acerrae and Mediolanum in 222 BC. Rome fought Carthage in the Second Punic War (218-201 BC), and the Gauls typically sided with Carthage. After the war, Rome took Bononia (196 BC), Placentia (194 BC) and Mutina (193 BC). After this, many of the surviving Boii retreated north across the Alps to form a new state, Boihaemum.