Following the failure of the 1757 Louisbourg Expedition, Forbes was promoted Brigadier general in December 1757 and given command of another attack on Fort Duquesne. His force contained 1,400 regulars, 400 from the Royal American Regiment, commanded by the experienced Swiss mercenary, Lt-Colonel Henry Bouquet, along with 1,000 Scots who made up Montgomerie's Highlanders. There were also 5,000 provincial militia from Virginia and Pennsylvania, commanded by George Washington, who had carried messages to Fort Duquesne in 1753, and accompanied Braddock in 1755.