
Pittsburgh, at the confluence of three rivers, is where the conflict between the French and British in the French and Indian War (1754–1763) began. The French built Fort Duquesne in 1754. General Braddock was defeated nearby in 1755. In 1758, the British took control and built Fort Pitt.
Pittsburgh was an important frontier outpost during the American Revolution. Settlers moved west through Pittsburgh. The region saw conflict with Native tribes allied with the British.
Pittsburgh became a major arsenal for the Union Army. Its steel factories produced weapons, ammunition, and armor for naval ships. The USS Monitor, the first American ironclad ship, was built with Pittsburgh steel.
The Homestead Strike of 1892 was an armed battle between steel workers and Pinkerton company detectives. It was one of the most violent and famous labor strikes in American history.