 Once all the Romans had at last marched through the foggy, narrow defile and entered the plains skirting the lake, trumpets were blown, signalling the general attack.The Carthaginian cavalry and infantry swept down from their concealed positions in the surrounding hills, blocked the road and engaged the unsuspecting Romans from three sides.Surprised and outmanoeuvred, the Romans did not have time to draw up in battle array, and were forced to fight a desperate hand-to-hand battle in open order.