The telephone patent was filed on February 14, 1876 on the behalf of the Scottish-born Alexander Graham Bell, who had been experimenting with devices to help the hearing-impaired in Boston. Like many inventions, several innovators had been working on related technologies. Bell’s application was filed two hours before another inventor, Elisa Gray. The patent was issued on March 7; three days later, Bell called for his assistant Thomas Watson: ‘Mr. Watson, please come here, I want you’ in the now-famous transmission between floors of his home.
Scientific American Inventions and Discoveries by Rodney Carlisle (Wiley, 2004)