The Union's key strategist and tactician in the West was Ulysses S. Grant, who won victories at Forts Henry (February 6, 1862) and Donelson (February 11 to 16, 1862), earning him the nickname of "Unconditional Surrender" Grant, by which the Union seized control of the Tennessee and Cumberland Rivers. Nathan Bedford Forrest rallied nearly 4,000 Confederate troops and led them to escape across the Cumberland. Nashville and central Tennessee thus fell to the Union, leading to attrition of local food supplies and livestock and a breakdown in social organization.