The Battle of Gettysburg was the greatest clash of arms on American soil, in American History. On the first day alone, July 1, 1863, Union forces lost 9,000 casualties; the Confederates lost 6,000 casualties, in one day, in the first day of battle. The Union forces were led by Maj. General George Meade, a steady, unimaginative,    and uninspiring general. He commanded one of the most resilient armies in history, the Army of the Potomac. The Confederate Army of Northern Virginia was commanded by one of the great generals in American arms, the hero of the Mexican-American War, General Robert E. Lee. It was an army fresh from the greatest feat of arms on American soil, the American Cannae, Chancellorsville, in which Lee had subdivided his inferior force into three parts and defeated the vast army of the North. General Lee, flushed with victory, had invaded the North, into Pennsylvania, on his way to Philadelphia or New York City; where there was a large pro-Southern community of Irish