Colonel John Singleton Mosby, known as the "Gray Ghost," was a Colonel in the Civil War, and lived for a time in Fauquier County in what is now the Town of Warrenton. He was noted for his lightning quick raids and his ability to successfully elude his pursuers (the Union Army) and disappear (like a ghost); an interesting man who, while a student at the University of Virginia in Charlottesville, served time in prison for shooting a fellow student, was known for his hot-tempered, lively personality.
After fighting in the First Battle of Bull Run, being promoted to First Lieutenant, being captured by the Union Army and imprisoned in the Old Capitol Prison in Washington, D.C., Mosby formed and commanded the 43rd Battalion, Partisan Rangers of the 1st Virginia Cavalry, also known as Mosby's Men.
Following the end of the Civil War, Mosby and President Grant became close friends, and Mosby served as the American consul to Hong Kong and in the U.S. Department of Justice.
Mosby was laid to rest in the Warrenton Cemetery.
For more information: https://en.wikipedia.org/wiki/John_S._Mosby