Major-General William Erskine commanded the Light Division during the battle. Wellington planned to have the Light Division and two brigades of cavalry circle behind Reynier's open left flank while the other four divisions attacked in front. When the day dawned with heavy fog, the other commanders decided to wait until visibility improved. Undeterred, Erskine peremptorily ordered Lieut-Colonel Thomas Sydney Beckwith's 1st Brigade forward. Instead of crossing the Côa beyond Reynier's flank, the brigade drifted to the left in the fog, crossed at the wrong location and struck the French left flank.