The emergence of heraldry as we know it today was linked to the need to distinguish participants quickly and easily in combat.
Distinguishing devices were used on surcoats ("coats of arms"), shields, and caparisoned horses, and it would have been natural for knights to use the same devices as those already used on their banners and seals.
Army units of the Roman Empire were identified by the distinctive markings on their shields (see left).
These were not heraldic in the medieval sense, as they were associated with military units, not individuals or families.
This continues in much of the world, though some heraldic authorities, notably Scotland, uses ovals for women's arms.
Officers of arms (Kings of Arms, Heralds and Pursuviants) practice heraldry and also rule on questions of rank or protocol.In heraldry, an escutcheon, or scutcheon, is the shield displayed in a coat of arms.