A heraldic badge, an emblem, an impresa, or device, or personal device worn as a badge indicates allegiance to, or the property of, an individual or family. Medieval forms are usually called a livery badge, and also a cognizance. They are para-heraldic, not necessarily using elements from the coat of arms of the person or family they represent, though many do, often taking the crest or supporters. Their use was more flexible than that of arms proper.
Badges worn on clothing were common in the late Middle Ages, particularly in England. They could be made of base metal, cloth or other materials and worn on the clothing of the followers of the person in question; grander forms would be worn by important persons, with the Dunstable Swan Jewel in enamelled gold a rare survivor. Livery collars were also given to important persons, often with the badge as a pendant. The badge would also be embroidered or appliqued on standards, horse trappings, livery uniforms, and other belongings. Many medieval badges survive in English pub names.
In the fourteenth, fifteenth, and sixteenth centuries, well-known badges were borne by the followers, retainers, dependants, and partisans of famous and powerful personages and houses, precisely because they were known and understood. (In contrast, the coat of arms was used exclusively by the individual to whom it belonged.)
Badges are occasionally taken from a charge in the bearer's coat of arms, or they have a more or less direct reference to those charges. More often, badges commemorated some remarkable exploit, illustrated a family or feudal alliance, or indicated some territorial rights or pretensions. Some badges are rebuses, making a pun or play-on-words of the owner's name. It was not uncommon for the same personage or family to use more than one badge; and, on the other hand, two or more badges were often borne in combination, to form a single compound device.