On March 18, 1816, Pittsburgh was incorporated as a city. Pittsburgh was named in 1758 by General John Forbes in honor of British statesman William Pitt, 1st Earl of Chatham. Allegheny County was created Sept. 24, 1788, from parts of Washington & Westmoreland counties. On Dec. 18, 1788, Allegheny County Court of Common Pleas & Quarter Sessions divided the county into seven townships, including Pitt Twp. On April 22, 1794, the Borough of Pittsburgh was incorporated.