The correct answer is "Comitatus."
The relationship between germanic leaders and their nobles (warriors) in which the warriors swore complete allegiance to the king or leader and the leader, in turn, took care of the needs of his warriors, including payment of debts was known as the comitatus.
Used by the Warrior germanic tribes, under a comitatus an individual pledged allegiance to the leader of the germanic tribe. The term is an ancient one used since the times of the Roman Empire. Technically, comitatus meant that the server would be side to side with the leader in the battlefield and never abandon it.