THE BICORNE:

The bicorne or bicorn—a two-cornered hat—is a historical hat widely adopted in the 1790s as an item of uniform by Europe and American army and naval officers. Most generals and staff officers of the Napoleonic period also wore bicornes, which survived as widely-worn full-dress headdress until the 20th century. Like the tricorne, it is still in use today for military ceremonial dress uniforms.