John Moses Browning's most famous Valentine's gift to gun owners was U.S. Patent 984,519 for a handgun later known just as the 1911.

The 15-page patent application, filed Feb. 17, 1910, included 38 points of claim and three sheets of drawings, building on Browning's previous 1897 patent (#580,924) for a magazine pistol. 

The patent was issued Feb. 14, 1911, and the rest, as they say, is history. 
 

While Colt first put the 1911 into production as the Government Model for both U.S. military and commercial contracts, other makers soon started producing the pistols during the Great War, a development that repeated itself with the updated M1911A1 during WWII, and unlicensed copies have been floating around since at least the 1920s. 
 

Today, most pistol makers both large and small have either keep a 1911-style pistol in their catalog, have made one in the past, or plan at some point to produce one in the future. 

Odds are the design still has another 111 years left in it.