The Phrygian cap , also known as Thracian cap and liberty cap, is a soft conical cap with the apex bent over, associated in antiquity with several peoples in Eastern Europe, Anatolia, and Asia. The Phrygian cap was worn by Thracians, Dacians, Persians, Medes, Scythians, Trojans, and Phrygians after whom it is named. The oldest known depiction of the Phrygian cap is from Persepolis in Iran.
Although Phrygian caps did not originally function as liberty caps, they came to signify freedom and the pursuit of liberty first in the American Revolution and then in the French Revolution, particularly as a symbol of Jacobinism (in which context it has been also called a Jacobin cap). The original cap of liberty was the Roman pileus, the felt cap of emancipated slaves of ancient Rome, which was an attribute of Libertas, the Roman goddess of liberty. In the 16th century, the Roman iconography of liberty was revived in emblem books and numismatic handbooks where the figure of Libertas is usually depicted with a pileus. The most extensive use of headgear as a modern symbol of freedom in the first two centuries after the revival of Roman iconography was made in the Netherlands, where it became popular headdress. In the 18th century, the traditional liberty cap was widely used in English prints, and from 1789 also in French prints; by the early 1790s, it was regularly used in the Phrygian form.
It was adopted in place of a crown on the coats of arms of the Argentina, Cuba, and Nicaragua republics as a symbol of their struggle for liberation and independence. It thus came to be identified as a symbol of republican government. A number of national personifications, including France's Marianne and the United States' Columbia are commonly depicted wearing the Phrygian cap.
Protagonists of the Belgian comic series The Smurfs wear white Phrygian caps. It is the national female headdress of the Caucasian Ingush people, who call it a kurkhars.