The Battle of Shiloh became the first horrific US Civil War battle. The amount of casualties on each side was staggering. Confederate General Albert Sidney Johnston's plan was to launch a surprise attack on the forces under General US Grant, before other Union troops under General Buell could reach Pittsburg Landing. Grant had reached the Landing but felt secure, secure enough to not build proper fortifications. It was a two day battle in early April in 1862. In the first day of the conflict, General Johnston died of a bullet wound. This left Confederate General Beauregard in charge for the following day. Prior to dawn, Buell's forces arrived and reinforced Grant's troops. It was a pitched battle and when Beauregard learned his own reinforcements would not arrive in a timely manner, he had to withdraw his forces and make way to Corinth, Mississippi. Casualties number cannot be exact, however, the best estimate is over 20,000 combined in the two day battle.