King
From Medieval Wiki
King - The highest rank any member of the nobility could reach.
Basically, a king is the ruler of the area inside his country in his realm. He had all the power anyone could want at the time. In times of war the king would go out of the country on Crusades or other war expeditions with his best knights and try to add to his country or help a friend.
A king's wife is called a queen. Many countries did not allow women to be monarchs in their own right; but where one did, she was also called a queen.
