The Battle of Fort Duquesne was a British assault on the eponymous French fort (later the site of Pittsburgh) that was repulsed with heavy losses on 14 September 1758, during the French and Indian War. After repulsing this advance party the French, deserted by some of their native allies and vastly outnumbered by the approaching Forbes, blew up their magazines and burnt Fort Duquesne. In November the French withdrew from the Ohio Valley and British colonists erected Fort Pitt on the site.