Difference (heraldry)

In heraldry, cadency is any systematic way of distinguishing otherwise identical coats of arms belonging to members of the same family. Cadency is necessary in heraldic systems in which a given design may be owned by only one person at once, generally the head of the senior line of a particular family. Because heraldic designs may be used by sons whilst their father is still alive, some form of differencing is required so as not to usurp the father's arms, known as the "undifferenced" or "plain coat". Historically arms were only heritable by males and therefore cadency marks have no relevance to daughters, except in the modern era in Canadian and Irish heraldry. These differences are formed by adding to the arms small and inconspicuous marks called brisures, similar to charges but smaller. They are placed on the fess-point, or in-chief in the case of the label. Brisures are generally exempt from the rule of tincture. One of the best examples of usage from the medieval period is shown on the seven Beauchamp cadets in the stained-glass windows of St Mary's Church, Warwick.

In heraldry's early period, uniqueness of arms was obtained by a wide variety of devices, including change of tincture and addition of an ordinary. See Armorial of Capetians and Armorial of Plantagenet for an illustration of the variety.

Systematic cadency schemes were later developed in England and Scotland, but while in England they are voluntary (and not always observed), in Scotland they are enforced through the statutorily required process of matriculation in the Public Register.

The English system of cadency involves the addition of these brisures to the plain coat:

Daughters have no special brisures, and normally use their father's arms on a lozenge, together with any marks of cadency their father may use. This is because English heraldry has no requirement that women's arms be unique. On marriage, they impale their father's arms to the sinister with those of their husband to the dexter, unless the woman happens to be an heraldic heiress, into which case her father's arms are borne on an inescutcheon on her husband's arms.

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