In 1755, Washington served voluntarily as an aide to General Edward Braddock, who led a British expedition to expel the French from Fort Duquesne and the Ohio Country. On Washington's recommendation, Braddock split the army into one main column and a lightly equipped "flying column". Suffering from a severe case of dysentery, Washington was left behind, and when he rejoined Braddock at Monongahela the French and their Indian allies ambushed the divided army. Two-thirds of the British force became casualties, including the mortally wounded Braddock. Under the command of Lieutenant Colonel Thomas Gage, Washington, still very ill, rallied the survivors and formed a rear guard, allowing the remnants of the force to disengage and retreat. During the engagement, he had two horses shot from under him, and his hat and coat were bullet-pierced. His conduct under fire redeemed his reputation among critics of his command in the Battle of Fort Necessity, but he was not included by the succeeding commander (Colonel Thomas Dunbar) in planning subsequent operations.