The Battle of Gettysburg began on July 1, 1863. Emboldened by his victory at Chancellorsville, Confederate General Robert E. Lee had decided to invade the North. In September of the previous year, he had ventured north into Maryland where, at Antietam, the bloodiest day of the war occurred. Although the battle was a draw, Lee's invasion was turned back, but the next summer he made another foray northward.
On June 30, General John Buford of the Union's Army of the Potomac and his cavalry had taken possession of Seminary Ridge west of Gettysburg. Union General George Reynolds arrived with the First Corps on July 1 to assist Buford. Reynolds opened the battle but was struck by a bullet and killed before noon. His death set the tone for the day. Both armies suffered devastating losses on the first day of the battle, but Union losses proved much greater. While the first day of the battle was counted as a Confederate victory, the tide turned on July 2 and the battle came to be viewed as the turning point of the Civil War.