The Military Secret They Hid About Harriet Tubman Most people know Harriet Tubman freed slaves on the Underground Railroad, but almost no one knows she led the only military raid in American history commanded by a woman. On June 2, 1863, Tubman directed 150 Black Union soldiers in the Combahee River Raid, liberating over 750 enslaved people in a single night. Born into slavery in 1821, she survived a skull fracture that caused lifelong seizures, escaped to freedom in 1849, and became a Union spy