at Corinth, Mississippi. Brigadier General William Tecumseh Sherman assured Grant that his green troops were ready for an attack. Grant agreed and wired Halleck with their assessment. Grant wanted to attack the Confederates at Corinth, but Halleck ordered him not to attack until Major General Don Carlos Buell arrived with his division of 25,000. Meanwhile, Grant prepared for an attack on the Confederate army of roughly equal strength. Instead of preparing defensive fortifications between the Tennessee River and Owl Creek, and clearing fields of fire, they spent most of their time drilling the largely inexperienced troops while Sherman dismissed reports of nearby Confederates. Union inaction created the opportunity for the Confederates to attack first before Buell arrived. On the morning of April 6, 1862, Grant's troops were taken by surprise when the Confederates, led by Generals Albert Sidney Johnston and P. G. T. Beauregard, struck first "like an Alpine avalanche" near Shiloh church, attacking five divisions of Grant's army and forcing a confused retreat toward the Tennessee River. Johnston was killed and command fell upon Beauregard. One Union line held the Confederate attack off for several hours at a place later called the "Hornet's Nest", giving Grant time to assemble artillery and 20,000 troops near Pittsburg Landing. The Confederates finally broke through the Hornet's Nest to capture a Union division, but "Grant's Last Line" held the landing, while the exhausted Confederates, lacking reinforcements, halted their advance. The day's fighting had been costly, with thousands of casualties. That evening, heavy rain set in. Sherman found Grant standing alone under a tree in the rain. "Well, Grant, we've had the devil's own day of it, haven't we?" Sherman said. "Yes," replied Grant. "Lick 'em tomorrow, though." Bolstered by 18,000 fresh troops from the divisions of Major Generals Buell and Lew Wallace, Grant counterattacked at dawn the next day and regained the field, forcing the disorganized and demoralized rebels to retreat back to Corinth. Halleck ordered Grant not to advance more than one day's march from Pittsburg Landing, stopping the pursuit of the Confederate Army. Although Grant had won the battle the situation was little changed, with the Union in possession of Pittsburg Landing and the Confederates once again holed up in Corinth. Grant, now realizing that the South was determined to fight and that the war would not be won with one battle, would later write, "Then, indeed, I gave up all