After the US victory at Fort Donelson in February 1862, Union General Henry Halleck, who was then commanding the Department of the Missouri, was relieved of command and reassigned to Washington, D.C. This decision was made by US President Abraham Lincoln and Secretary of War Edwin M. Stanton, who were dissatisfied with Halleck's perceived slow and cautious military strategy, particularly during the battles at Fort Donelson and Fort Henry in Tennessee. Halleck's actions were viewed as overly cautious, lacking in aggression, and not capitalizing on the opportunities for further successes against Confederate forces. Consequently, he was replaced in the field by General Ulysses S. Grant, who went on to lead the Union to significant victories in subsequent campaigns.