These are the kings that reigned in the land of Edom before any king reigned among the children of Israel: Bela the son of Beor, and the name of his city was Dinhabah.

But after the death of Hadad, there were dukes in Edom:

duke Magdiel and duke Iram. These were the dukes of Edom.

and put Soldiers in Edom, and all Edom became David's servants: for the LORD kept David in all that he took in hand.