Erskine, who was very nearsighted and mentally unbalanced, then became cautious and issued explicit instructions to Colonel George Drummond not to support his fellow brigade commander. At this point, Erskine rode off to join the cavalry, leaving the Light Division leaderless for the rest of the battle. Reynier switched most of his 10,000-man corps against Beckwith's 1,500 and pressed the light infantry back. When Drummond heard the sounds of battle approaching, he deduced that Beckwith's men were retreating. Disobeying orders, Drummond led his 2nd Brigade across the Côa and joined Beckwith. Together they drove the French back.