per bend crenelle
To add variety and interest to the arms, heraldic artists began to divide the background of the shield into two parts, giving each a different colour. They were named for the ordinary that they most resembled, so the diagonal division of the shield, similar to the ordinary known as the bend came to be called per bend Understanding Signs & Symbols – Heraldry, S. Oliver & G. Croton, Quantum, London, 2013, P63. Visually rather striking, it became popular and artists added decorative effects to the partition line to distinguish otherwise very similar coats of arms. A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Party. An edge which is decorated like the top of a castle wall is said to be embattled, or sometimes crenelle, from the original French. (In castle building terminology the parts of the wall that stick up are known as merlons, and the resulting gaps as crenels). A whole sub-section of heraldic terminology has sprung up to describe whether these crennellations appear on which edges, whether they line up or alternate, have additional steps or rounded tops. The interested reader is directed to the reference for the full set! A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Embattled For obvious reasons, use of this decoration is to be associated with castles and fortified towns, an early authority, Guillim suggest also some association with fire, but with out clear reason The Symbolisms of Heraldry, W. Cecil Wade, George Redway, London, 1898 P41. In all, this is one of the more common, and most effective and appropriate of the decorative edges.