1 Land was determined by lot for the tribe of Manasseh, who was actually Joseph's oldest son. Gilead and Bashan belonged to Machir, who was Manasseh's oldest son and Gilead's father. This was because he was a warrior.
1
This was the allotment for the tribe of Manasseh as Joseph’s firstborn, that is, for Makir, Manasseh’s firstborn. Makir was the ancestor of the Gileadites, who had received Gilead and Bashan because the Makirites were great soldiers.