23:9 · Symbols of symbols are quite rare. Examples are signs in nautical charts which signify such navigation marks as balizes or beacons, and this pictorial sign for an object which itself is a symbol, the orb. The globe was a symbol of power used by he Roman emperors. At the top it was provided with a representation of the goddess of victory. This was replaced with the Christian cross by the Byzantine emperors.
    The sign within the circle most probably originates from the convenionalized medieval map of the world, .
    For more information about that map, look it up in Group 24.