Genesis 48:18

“On the west side shall be the standard of the camp of Ephraim by their armies, and the leader of the sons of Ephraim: Elishama the son of Ammihud,

And this was the lot for the tribe of Manasseh, for he was the firstborn of Joseph. To Machir the firstborn of Manasseh, the father of Gilead, were allotted Gilead and Bashan, because he was a man of war.

Now the sons of Reuben the firstborn of Israel (for he was the firstborn, but because he profaned his father’s bed, his birthright was given to the sons of Joseph the son of Israel; so that he is not recorded in the genealogy according to the birthright.