The Army of the Cumberland was a Union army that fought in the Western Theater of the American Civil War. It was formed in October 1862 from the remnants of the Army of the Ohio and the Army of Kentucky, and was commanded by Major General William Rosecrans.
The Army of Tennessee was a Confederate army that fought in the Western Theater of the American Civil War. It was formed in November 1862 from the merger of the Army of Mississippi and the Army of Tennessee (Western).
The Battle of Murfreesboro, also known as the Battle of Stones River, was fought from December 31, 1862, to January 2, 1863, in Rutherford County, Tennessee. It was a bloody and costly battle that ended in a stalemate, with both sides claiming victory.
Following the Battle of Murfreesboro, the Army of the Cumberland was tasked with securing the line of the Cumberland River north to Nashville, Tennessee. This would allow the Union to control a vital transportation route and would also put the Confederate Army of Tennessee at risk of being cut off from its supply lines.
The Army of the Cumberland was successful in its mission, and by the end of January 1863, it had secured the Cumberland River north to Nashville. This was a major victory for the Union, and it helped to pave the way for the eventual defeat of the Confederate Army of Tennessee.