Over the course of the night of 6 April, Buell’s 18,000-strong Army of the Ohio arrived, crossed the river and filed into position along the centre and left of the Union line. Further reinforcements arrived in the form of a reserve division commanded by Major General Lew Wallace, who joined the right of the Union line. Grant renewed the fighting by ordering an aggressive counterattack including Wallace and Buell’s reinforcements. Taken by surprise, General Pierre Gustave Toutant-Beauregard, who had assumed command of the Confederate army on the death of Johnston the previous afternoon organized a tenacious defense by rallying 30,000 of his troops. For a while the Confederates halted the Union surge. However, the sheer weight of numbers began to tell. By mid-afternoon the Union right had advanced back to the Shiloh Church and, realizing the worsening position of his army, Beauregard began a general retreat. The surviving Confederates withdrew, covered by artillery commanded by Breckenridge, fleeing south to their fortified positions at Corinth. The Union armies were content to take possession of the grisly battlefield, too exhausted to follow. Both sides in this war were deeply shocked when the casualties became known, 27,746 Americans had been killed, wounded or were missing.
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