While the phenomenon of heresy played a significant role in medieval society, it also found its reflection and interpretation in art. The present article concerns schemata of composition applied in representations which have an anti-heretical topic, or only theme, and attempts to define the figure of a heretic through costume or physiognomy. Also, it strives to answer the question to what extent medieval art reflected the stereotype, prevalent in contemporary literature, of a heretic. A discussion between representatives of the Roman church and heretics is the topic of, among others, the mid-11th-century miniatures on frontispieces of manuscripts from the Mont St. Michel monastery (St. Augustine in conversation with Manicheans). Such discussion is a topic frequent also in art of the late Middle Ages. Among saints who due to their activity had to deal with heretics, St. Peter the Martyr and St. Dominic seem to be the most representative. It is possible to ascertain that artists attempted to identify heretics especially through their costume, facial expression and gestures.Depicting heretics in an Oriental costume is a phenomenon typical only for the late-medieval art. The earlier artists also tried to distinguish and define a heretic through dress, but they presented this figure usually in layman's clothing, which contrasted with the clerical dress proudly worn by his Catholic adversary.The fact that heretics, Jews, Muslims and sorcerers are represented in art in a similar way not only attests to the conviction that many heresies were of Eastern origin, but also refers to the division of the world introduced by St. Augustine. Catholic authors placed heretics, together with the Jews, unbelievers, heathens, sinners, criminals, bandits and sorcerers, in the devil's realm. Books are frequently an attribute of heretics, and almost always of heresiarchs. Heretic writings are confronted with and defeated by orthodox texts in the same way the person of a heresiarch is defeated by a representative of the Roman Church. They are often depicted lying cover up on the ground, thus displaying their own falsity and failure.