A number of cross symbols were developed for the purpose of the emerging system of heraldry, which appeared in Western Europe in about 1200. This tradition is partly in the use of the Christian cross an emblem from the 11th century, and increasingly during the age of the Crusades. Many cross variants were developed in the classical tradition of heraldry during the late medieval and early modern periods. Heraldic crosses are inherited in modern iconographic traditions and are used in numerous national flags.