overking

noun

1. A king who has sovereignty over inferior kings or ruling princes; a ruler of an overkingdom; a king that is truly superior or supreme; an emperor.

   “the King of Connaught, who was recognized as overking of the island by the rest of the tribe[…]”

   “"They have given me five-and-twenty overkings," protested John, and he at once turned to seek a way of evasion.”

   “The latter asked the aid of Cond the overking, who took up their cause, and a fierce war arose, in which Cond was beaten and compelled to divide Ireland with his rival.”

   “Celtic law, however, explicitly specified that any member of a tribe, including overkings/overqueens of provinces and Druid high priests/priestesses, could be stripped of their legal rights if they failed to execute the legal obligations of their stations.”

   “The difference between a dux bellorum and an overking is not clear, and it may be that the two concepts were elided into a single role.”