In February 1862, after Union Gen. Ulysses S. Grant captured Fort Henry and moved against Fort Donelson, Confederate defenders at Fort Donelson repulsed Flag Officer Andrew H. Foote's gunboat fleet on February 14, but continued Federal reinforcements led Confederate Gen. John B. Floyd to order a dawn attack on the Union right flank to open an escape route. Col. Nathan Bedford Forrest and his cavalry led the way as Confederate infantry forced Union Gen. John A. McClernand's division back from the Cumberland River. Forrest tried to turn the Federal right, charged an Illinois battery and captured its guns before losing his horse, then outflanked the 11th Illinois Volunteers after stubborn resistance and forced them to retreat with heavy Union losses. When the Confederate drive stalled before Capt. Edward McAllister's 1st Illinois Light Artillery, Forrest made two unsuccessful charges, then joined the 2nd Kentucky Infantry to overwhelm the battery after supporting Union infantry fled. The road of escape from Fort Donelson was opened but closed the next day, and part of Floyd's command escaped by boat on February 16 while the rest surrendered to Grant. The attack succeeded largely because Forrest used massed cavalry in the hottest part of the battlefield, helping transform cavalry in the West beyond scouting, screening infantry movements, and pursuing retreating forces into independent large-scale raids.