Genesis 36:40
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, 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,
The chapter that holds this verse is wholly taken up with Esau, that is Edom, and the nations and descendants that sprang from him.
It comes ten or eleven years after Jacob's blessing at Peniel, after his meeting with Esau and his coming in peace to Shechem, and after the destruction of Shechem.
It comes after the revival in Jacob's family when they put away their idols and God renewed His promises to Jacob, and after the death of Rachel and the birth of Benjamin and the sin of Reuben.
It comes after the death of Isaac at 180 years old, when Esau and Jacob probably met for the last time.
At that time Jacob was about 109 years old, Joseph was 17, and Benjamin was a small child two to four years old.