Two inventors filed rival telephone claims on the very same day

On 14 February 1876, lawyers for Alexander Graham Bell and Elisha Gray each filed papers with the US Patent Office describing a way to transmit speech electrically — hours apart. Bell's patent was granted first, making him the telephone's legal inventor, but the closeness of the filings sparked a controversy over independent invention still argued over today.

— Wikipedia contributors, Elisha Gray and Alexander Bell telephone controversy — 14 February 1876