count palatine

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various noblemen originally exercising certain royal powers within their own domains, especially a count of the Holy Roman Empire having sovereign powers in his own territories.
• noun A feudal lord having sovereign powers over his lands.
• noun The titled proprietor of a county palatine in England or Ireland.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a count who exercised royal authority in his own domain