Fort Prince George was an uncompleted fort on what is now the site of Pittsburgh, at the confluence of the Allegheny and Monongahela Rivers in Allegheny County, Pennsylvania. The site was originally a trading post established by Ohio Company trader William Trent in the 1740s. Fort Prince George (named for the crown prince, later King George III) was started in January 1754 by 41 Virginians in 1754. The plan to occupy the strategic forks was formed by Virginia Lieutenant Governor Robert Dinwiddie with the advice of Lieutenant Colonel George Washington, who Dinwiddie had sent on a mission to warn French commanders in late 1753, and who had made a military assessment of the site. Captain Trent was in command of the force that was constructing the fort, which was driven off by a force of 1,000 French and Indians led by Claude-Pierre Pécaudy de Contrecœur.