The tricorne or tricorn is a style of hat that was popular during the 18th century, falling out of style by 1800, though actually not called a "tricorne" until the mid-19th century. During the 18th century, hats of this general style were referred to as "cocked hats". At the peak of its popularity, the tricorne varied greatly in style and size, and was worn not only by the aristocracy, but also as common civilian dress, and as part of military and naval uniforms. Typically made from animal fiber, the more expensive being of beaver-hair felt and the less expensive of wool felt, the hat's most distinguishing characteristic was that three sides of the brim were turned up (cocked) and either pinned, laced, or buttoned in place to form a triangle around the crown. The style served two purposes: first, it allowed stylish gentlemen to show off the most current fashions of their wigs, and thus their social status; and secondly, the cocked hat, with its folded brim, was much smaller than other hats and therefore could be more easily tucked under an arm when going inside a building, where social etiquette dictated that a gentleman should remove his hat. Tricornes with laced sides could have the laces loosened and the sides dropped down to provide better protection from the weather, sun, and rain.
Tricornes had a rather broad brim, pinned up on either side of the head and at the back, producing a triangular shape. The hat was typically worn with one point facing forward, though it was not at all unusual for soldiers, who would often rest a rifle or musket on their left shoulder, to wear the tricorne pointed above their left eyebrow to allow better clearance. The crown is low, unlike the steeple hats worn by the Puritans or the top hat of the 19th century.
Tricornes ranged from the very simple and cheap to the extravagant, occasionally incorporating gold or silverlace trimming and feathers. In addition, military and naval versions usually bore a cockade or other national emblem at the front. This style of hat remains in use in a number of countries to the present day as an item of ceremonial dress.
The tricorne appeared as a result of the evolution of the broad-brim round hat used by Spanish soldiers in Flanders during the 17th century. By pledging (binding) the brims, a triangular shape was obtained. This shape was favored by Spanish soldiers, as when standing at arms their muskets could be held at their shoulders right or left without hitting the hat brim. War broke out between France and Spain in 1667 over the Spanish Netherlands, and during the subsequent struggle its use spread to the French armies. The style was brought back to France, where its usage spread to the French population and the royal court of King Louis XIV, who made it fashionable throughout Europe, both as a civilian and military wear. By the end of the 17th century, the tricorne was popular in both civilian fashion and in military uniforms. They remained one of the predominant European styles of hat throughout the 18th century. In the United States, only the first five Presidents, from George Washington to James Monroe, wore this style of hat according to the fashion of the 18th century. James Monroe earned the nickname "The Last Cocked Hat" because of this.
The tricorne quickly declined in use at the end of the 18th century. It evolved into the bicorne, which was widely used by military officers in Europe from the 1790s until World War I, not completely fading out of style until World War II. For enlisted soldiers, the tricorne was replaced by the shako at the turn of the 19th century, which had become the new dominant style of military headgear from 1800 on. Also at the turn of the 19th century, as the fashionable hat for civilian men, the tricorne was overtaken by the top hat. In 1917, the Women's Royal Naval Service introduced a smaller, modernised version of the tricorne for female officers.