The Purple Heart / Badge of Military Merit
It's routinely called America's oldest military award, and by creation date that's true — but the medal you know today spent nearly 150 years not existing at all.
How it actually works
George Washington created the Badge of Military Merit at Newburgh, New York, on August 7, 1782: a purple, heart-shaped piece of silk edged in silver binding with "Merit" stitched across it. The Continental Congress had barred Washington from granting battlefield promotions to recognize merit, so he created the badge instead — and deliberately for enlisted soldiers and non-commissioned officers, an idea no European army of the era had, since decorations there were reserved for officers. Only three Revolutionary War soldiers are known to have received it: Elijah Churchill, William Brown, and Daniel Bissell Jr.
The badge is often described as America's oldest continuously awarded military decoration, and the "oldest" part is true by creation date — but "continuously" is not. After those three Revolutionary War recipients, the badge fell completely out of use. It was not revived until February 22, 1932, the 200th anniversary of Washington's birth, when the War Department brought it back as the modern Purple Heart, redesigned by Army heraldic specialist Elizabeth Will with Washington's profile added to the medal. The idea is 1782; the medal in current use is a 1932 revival that sat dormant for roughly a century and a half in between.
Created by George Washington, August 7, 1782; lapsed after the Revolutionary War; revived February 22, 1932.