Excerpts from Books and Wikipedia
"Fort Duquesne (...) was a fort established by the French in 1754, at the confluence of the Allegheny and Monongahela rivers. It was later taken over by the English, and later Americans, and developed as Pittsburgh in the U.S. state of Pennsylvania. Fort Duquesne was destroyed by the French, prior to English conquest during the Seven Years' War, known as the French and Indian War on the North American front. The latter replaced it, building Fort Pitt between 1759 and 1761. The site of both forts is now occupied by Point State Park, where the outlines of the two forts have been laid in brick." [Wikipedia] "In 1752 a new governor, the marquis de Duquesne, was sent to Canada, with instructions to reassert possession of the Ohio Valley and thus the geographical link with Louisiana. In 1754 he built a fort at the confluence of the Allegheny and Monongahela rivers, which together form the Ohio river, and named it after himself. By that point it was only a matter of time before the undeclared war with Great Britain was made official." [Blanning: Pursuit of Glory, p. 577]