I also wanted a number that would be alliterative if used in a motto, and I've always liked the motto 'Fighting SeaBees' from WWII. I wanted something that sounded military, had a big number, and ended in a 'one' to give it a little authenticity. The real story behind the name '501st' is rather unremarkable.

(as told by Albin Johnson, Founder of the 501st Legion)