 Santa Anna had established a strong defensive position, but he left his left flank undefended on the assumption that dense trees made the area impassible.Scott decided to attack Santa Anna's position on two fronts, sending a force led by David E. Twiggs against Santa Anna's left flank, while another force, led by Gideon Pillow, would attack Santa Anna's artillery.In the Battle of Cerro Gordo, Pillow's force was largely ineffective, but Twiggs and Colonel William S. Harney captured the key Mexican position of El Telegrafo in hand-to-hand fighting.