Many interesting examples of early playing cards are found in the museums of Europe, and there are also noteworthy specimens in the cabinets of various private collectors. A few hand-painted decks exist which are extremely artistic. These depict various important personages contemporary with the artists. In some instances, the court cards are portraitures of the reigning monarch and his family. In England engraved cards became popular, and in the British Museum are also to be seen some extremely quaint stenciled cards. Heraldic devices were employed; and Chatto, in his Origin and History of Playing Cards, reproduces four heraldic cards in which the arms of Pope Clement IX adorn the king of clubs. There have been philosophical decks with emblems chosen from Greek and Roman mythology, also educational decks ornamented with maps or pictorial representations of famous historic places and incidents. Many rare examples of playing-cards have been found bound into the covers of early books. In Japan there are card games the successful playing of which requires familiarity with nearly all the literary masterpieces of that nation. In India there are circular decks depicting episodes from Oriental myths. There are also cards which in one sense of the word are not cards, for the designs are on wood, ivory, and even metal. There are comic cards caricaturing disliked persons and places, and there are cards commemorating various human achievements. During the American Civil War a patriotic deck was circulated in which stars, eagles, anchors, and American flags were substituted for the suits and the court cards were famous generals.