In heraldry, an escutcheon () is a shield that forms the main or focal element in an achievement of arms. The word can be used in two related senses. In the first sense, an escutcheon is the shield upon which a coat of arms is displayed. In the second sense, an escutcheon can itself be a charge within a coat of arms. Escutcheon shapes are derived from actual shields that were used by knights in combat, and thus are varied and developed by region and by era. Since shields have been regarded as military equipment appropriate for men only, British ladies customarily bear their arms upon a lozenge, or diamond-shape, while clergymen and ladies in continental Europe bear their arms upon a cartouche, or oval. Other shapes are also in use, such as the roundel commonly used for arms granted to Aboriginal Canadians by the Canadian Heraldic Authority, or the Nguni shield used in African heraldry (likewise, Christian organisations and Masonic bodies tend to use the same shape, also known as a vesica piscis). Although an escutcheon can be used as a charge on its own, the most common use of an escutcheon charge is to display another coat of arms as a form of marshalling. Such escutcheon charges are usually given the same shape as the main shield. When there is only one escutcheon charge, it is sometimes called an inescutcheon. The word escutcheon (late 15th century) is based on Old North French escuchon ('shield'). Shapes The earliest depictions of proto-heraldic shields in the second half of the 12th century still have the shape of the Norman kite shield used throughout the 11th and 12th centuries. By about the 1230s, shields used by heavy cavalry had become shorter and more triangular, now called heater shields. Transitional forms intermediate between kite and heater are seen in the late 12th to early 13th centuries. Transition to the heater was essentially complete by 1250. For example, the shield of William II Longespée (d. 1250) shown with his effigy at Salisbury Cathedral is triangular, while the shield shown on the effigy of his father William Longespée, 3rd Earl of Salisbury (d. 1226) is still of a more elongated form. The shield on the enamel monument to Geoffrey V, Count of Anjou (d. 1151) is of almost full-body length. The heater was used in warfare during the apogee of the Age of Chivalry, at