Mark Twain was granted U.S. Patent No. 121,992 for an adjustable and detachable garment strap on December 19, 1871.
Notes on verification
Confirmed via USPTO/Google Patents record and corroborated by multiple credible sources including USPTO's own historical page on Twain.
Sources
- Unswerving irregularity | USPTO (uspto.gov)
- https://patents.google.com/patent/US121992A/en (patents.google.com)
- https://www.marktwainhouse.org/ (marktwainhouse.org)