In February 1862, as a combined army-navy offensive by Union forces threatened Fort Henry on the Tennessee River, its Confederate defenders escaped to nearby Fort Donelson on the Cumberland River. Maps reflected Donelson’s well-defended position on high ground, but not its ineffective Confederate leadership. Brigadier General Ulysses S. Grant (1822–1885) exploited a weakness in the lines following a Confederate attack, allowing Union troops to close in on the fort. When asked for terms by Grant’s old friend Simon Bolivar Buckner, the officer left in command after the original commander had escaped, Grant replied, “No terms except unconditional and immediate surrender.”