The principal vehicle for displaying the heraldic devices is the shield. The type and position of the helm indicates the rank of the bearer. In the late 15th century great nobles, and later certain corporations, were accorded supporters, creatures on either side of their shields to support them. The whole display is called an achievement of arms. In the design of arms a wide variety of symbols are used, depicted and arranged according to a series of conventions.
Younger sons add small symbols, called marks of cadency, to their arms and crests.
Arms are insignia of honour and so are protected by law. Today only the European monarchies, Ireland, Switzerland, South Africa, and Zimbabwe control the use of arms. In some countries there is non-noble or burgher heraldry, but this generally enjoys no protection. Tinctures are hues used in heraldry, which are denoted colours, metals, and furs. The symbols used in heraldry are called charges.