In to the summer of 1863, the Confederate army led by Lee played for keeps by giving a big contingent towards North, as much as Pennsylvania. It clashed due to the Union military at Gettysburg, where in actuality the biggest battle ever become battled on American soil happened. After three days of hopeless battle, the Confederates must acknowledge their beat. At Gettysburg, the Potomac military Union artillery contributed to support the Confederate advance, impacting the outcomes of this battle.