Before revision: It is derived from a medieval form where the spear was drawn across the shield, which in turn was based on a convention used in antquity which represented Mars a spear.Bianchini's planisphere, produced in the 2nd century, shows Greek personifications of planetary gods charged with early versions of the planetary symbols.
After revision: It is derived from a medieval form where the spear was drawn across the shield, which in turn was based on a convention used in antiquity which represented Mars a spear.Bianchini's planisphere, produced in the 2nd century, shows Greek personifications of planetary gods charged with early versions of the planetary symbols.