Margrave

(G. markgraf, mark, march + graf, earl or count)

A margrave was originally the military governor of a German "Mark" or march, a medieval border province. As outlying areas tended to be of great importance to the central realms of kings and princes, and they often were larger than those toward the interior, margraves assumed quite inordinate powers over those of other "earls" of a realm.
In medieval Europe the most important provinces so called were the "Mark Brandenburg" and Austria.

Later, the title became hereditary and is now considered the equivalent of a marquess, in France of a marquis.