sentences:  A collection of tribes, each led by a noble, forms a confederation called "amanokal", whose chieftain is elected from among the nobles by the tribal chiefs.The chieftain is the overlord during times of war, and receives tribute and taxes from tribes as a sign of their submission to his authority.The vassal-herdsmen are the second free strata within Tuareg society, occupying a position just below that of the nobles.