The primary Union forces in this theater were the Army of the Tennessee and Army of the Cumberland, named for the two rivers, Tennessee River and Cumberland River. After Meade's inconclusive fall campaign, Lincoln turned to the Western theater for new leadership. At the same time, the Confederate stronghold of Vicksburg surrendered, giving the Union control of the Mississippi River, permanently isolating the western Confederacy, and producing the new leader Lincoln needed, Ulysses S. Grant.