The battle was fought over two days. As was customary of the warfare of the period, both armies deployed their cavalry on the wings and infantry in the center. Pyrrhus held his personal cavalry in reserve behind the centre under his own command. The elephants were also initially held in reserve. On the first day, the Greek cavalry and elephants went largely unused as they were blocked from the Roman advances by woodland and hills in the vicinity of the battleground, although the Italic soldiers in the phalanxes reportedly engaged the Romans very effectively. Pyrrhus's Macedonians broke the Roman first legion and Rome's Latin allies on their left wing but the Roman third and fourth legions overcame the Tarentines, Oscans and Epirotes in Pyrrhus' centre. Meanwhile, a force of Dauni attacked the Greek camp. Pyrrhus dispatched reserve cavalry to deal with the breakthrough along with part of the regular horse and several elephants. When the attackers withdrew to an almost inaccessible position atop a steep hill, Pyrrhus deployed the elephants against the third and fourth legions, who likewise proceeded to take refuge in heavily wooded areas on high ground while remaining under constant fire from the archers and slingers escorting the elephants. Pyrrhus sent Athamanian, Acharnian and Samnite infantry to drive the Romans out of the woods, but those forces were intercepted by Roman cavalry. Both sides withdrew at dusk, neither having gained a significant advantage. At dawn, Pyrrhus sent light infantry to occupy the treacherous high ground which had proven to be the cause of stalemate the previous day, thereby forcing the Romans to fight in the open or flee. As at Heraclea, the infantry and cavalry engaged in a massive line collision, until the elephants, supported by light infantry, broke through the Roman line. As a result, the specialized anti-elephant Roman devices were quickly deployed by Roman commanders and officers; though briefly proving effective, the small force was eventually overwhelmed by Greek psiloi. The Romans succumbed to the combined pressure of the phalanx and elephants, which Pyrrhus ordered to advanced. Pyrrhus simultaneously ordered his personal cavalry to charge, beginning and quickly completing a significant rout. The defeated Roman force retreated.