August 7 is National Purple Heart Day, honoring the recipients of America’s oldest award for military merit.

Created by General George Washington as the Badge of Merit in 1782, it was awarded for “any singularly meritorious action” in battle.

That changed in 1931, when, at the behest of General Douglas MacArthur, the U.S. War Department created the Order of the Purple Heart and changed the badge design to bear Washington’s likeness. Criteria changed during World War II that made all members of the military eligible, but limited Purple Hearts only to those wounded in actions against an enemy. And the circumstances that merited the Purple Heart had to be documented. MacArthur became the first Purple Heart recipient.

While no accurate database exists, it is estimated that about 1.9 million Purple Hearts have been awarded. During World War II, the War Department stockpiled more than 1.5 million Purple Heart medals. Nearly 500,000 went unused after the atomic bombs dropped on Japan ended the war and with it, the need to invade Japan with ground forces that were predicted to suffer as many as 1 million casualties.

More than 370,00 of those remaining Purple Hearts went to those who fought in the Korean and Vietnam wars, and other campaigns. Some medals deteriorated in storage. The government didn’t order a new production until 1999, and since 2001 more than 30,000 have been presented.

Six U.S. Army soldiers share the record for the most Purple Hearts, with eight each.