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. [tier=bronze indep_score=0.525 clusters=2 claim_tier=notable | framework convergence=single on USPTO original patent record for US121992A (upstreams: USPTO patent database, Google Patents) — publishers independent, evidence may not be | kind=empirical eligibility=high]
Sources
- Unswerving irregularity | USPTO (seed:firsts_and_inventions)
- https://patents.google.com/patent/US121992A/en (corroboration)
- https://www.marktwainhouse.org/ (corroboration)