What took place that quite possibly saved grant from defeat at shiloh? confederate troops retreated suddenly due to heavy losses. union soldiers fought very well. buell arrived with reinforcements after the first day of battle. general prentiss was able to hold on to his position in the hornet's nest. reinforcements arrived from general sherman.

Buell arrived with reinforcements after the first day of battle
on the second day in the morning union forces numbered about 40 000 soldiers, an army of confederate under  beauregard only 30 000. beauregard did not know about the arrival of   buell and continue counting on victory. both sides carried out several attacks and counter-attacks, which have not been able to break the enemy line. beauregard finally realized that he can not win the battle and realizing their own losses, retreated back behind corinth. after a few days the chase confederate army grant returned to the starting positions. the confederates continued to retreat until the start of a new offensive in august 1862.