Blind Tom Wiggins was an autistic, blind savant who was born a slave in western Georgia and eventually became the highest-paid pianist of the 19th century. Though of course, those $100,000 per year (north of $1.5 million in today's money) went to his owners and not to him. For much of his life, Blind Tom was paraded as a circus-type curiosity. Although he never really gained independence, he became well recognized, playing at the White House and at venues across North America and Europe.
The Battle of Manassas (linked above) showcases his prodigious talents, recreating the Civil War battle with a variety of songs and anthems and imitations of fifes and drums. He wrote this when he was 12, shortly after the battle took place.
As a note, composer to composer, Wiggins uses Dixie, Yankee Doodle, and the Star-Spangled Banner while in my own response to the Civil War (Letters from the War, written 150 years after the fact), I also use Dixie and Yankee Doodle. Some musical signposts last a long time.
(A special thanks to John Muriesanu for bringing this story to my attention.)