The Battle of Antietam took place during the Civil War era between the Union Army of the Potomac and the Confederate Army of Northern Virginia. The battle took place on September 17, 1862 near Sharpsburg, Maryland and Antietam Creek as part of the Maryland Campaign. The Battle of Antietam is recognized in American history as the bloodiest one-day battle during the Civil War. Its recognition is based on the astonishing number of casualties compared to any other war. One in four soldiers engaged in the battle was killed, wounded, captured or listed as missing. The Battle of Antietam not only ended the first Confederate invasion of the North, but was also a turning point that allowed Abraham Lincoln to issue the Preliminary Emancipation Proclamation (NPS Maryland). General Lee, commander of the Confederate Army, wanted to invade the North for several reasons. Many of his reasons for this invasion included reducing pressure on the Shenandoah Valley – "the breadbasket of the Confederacy" – at harvest time; encourage European support for the Confederacy by winning a battle in the North; and demoralize Northerners to decrease their support for the war in hopes of encouraging the slave state of Maryland to join the Confederacy (Alexander, 2006). Days before the battle, General Robert E. Lee, commanding general for the Confederate Army of Northern Virginia, wrote a letter to President Jefferson Davis on September 3, 1982 stating that "the present appears to be the most propitious time since the beginning of the war for the Confederate Army to enter Maryland." He further stated that the Confederate Army could not afford to remain inactive even though it appeared weaker than its opponents in terms of men... middle of paper... Couch's division disbanded and finally a five-brigade cavalry division commanded by Brigadier General Alfred Pleasonton. McClellan's field artillery contained approximately 300 guns, arranged in six-gun batteries, with several batteries assigned to each division. Of the 300 weapons approximately 166 were rifled. (CITE) General Lee believed that the Union would need time to rebuild after months of campaigning and made the decision to divide his army, sending half of it to capture various objectives. One objective involved using part of Lt. Gen. Thomas "Stonewall" Jackson's corps to capture the Union garrison at Harpers Ferry, Virginia, while the larger corps, commanded by Lt. Gen. James Longstreet, headed toward Sharpsburg . Lee used order no. 191 to brief its commanders of their routes and objectives on 9 September. (Alexander 2006).