P. G. T. Beauregard
Robert Patterson (January 12, 1792 – August 7, 1881) was an Irish-born United States major general during the American Civil War, chiefly remembered for inflicting an early defeat on Stonewall Jackson, but crucially failing to stop Confederate General Joseph E. Johnston from joining forces with P. G. T. Beauregard at the First Battle of Bull Run. He is still blamed for this historic Union defeat.