Jerusalem cross

A cross potent, its arms ending in crutches, between four small crosses. Its whole grid comes from one circle: walk the compass round it from head to foot, swing the opening between the first two marks about both ends to find the level line, and the chords of the walk fall on the lines halfway out, where the small crosses stand. Only the widths are chosen. The Dean Tract of about 1340, the earliest known treatise on arms, gives the King of Jerusalem a shield of silver with crosses of gold: metal on metal. It states no rule against that; the later treatises that do state one name Jerusalem as the exception.