Genesis 36:40-43 - The Dukes of Edom

And these are the names of the dukes that came of Esau, according to their families, after their places, by their names; duke Timnah, duke Alvah, duke Jetheth, Duke Aholibamah, duke Elah, duke Pinon, Duke Kenaz, duke Teman, duke Mibzar, Duke Magdiel, duke Iram: these be the dukes of Edom, according to their habitations in the land of their possession: he is Esau the father of the Edomites.

Parallel Passage 1 Chronicles 1:51-54

Genesis 36:31 - Before Israel had a king

And these are the kings that reigned in the land of Edom, before there reigned any king over the children of Israel.

The children of Israel didn't have a king until about seven hundred years later when Samuel introduced Saul as the man the LORD had chosen to be their king (1 Samuel 10:24).

Genesis 27:40 - The Yoke Of The Edomites

And by thy sword shalt thou live, and shalt serve thy brother; and it shall come to pass when thou shalt have the dominion, that thou shalt break his yoke from off thy neck.

Esau had the dominion when Esau and Jacob met for their first time after Jacob fled to Padanaram (Genesis 33:3). In process of time, the Edomites (the descendants of Esau, Genesis 36:1) served the Tribe of Judah but gained their freedom during the time of King Joram (2 Kings 8:20).