On November 23, Grant organized three armies to attack at Missionary Ridge and Lookout Mountain. Two days later, Hooker's forces took Lookout Mountain. Grant ordered Major General George Henry Thomas to advance when Sherman's army failed to take Missionary Ridge from the northeast. The Army of the Cumberland, led by Major General Philip Sheridan and Brigadier General Thomas J. Wood, charged uphill and captured the Confederate entrenchments at the top, forcing a retreat. The decisive battle gave the Union control of Tennessee and opened Georgia, the Confederate heartland, to Union invasion. Grant was given an enormous thoroughbred horse, "Cincinnati", by a thankful admirer in St. Louis.