A Fremen ritual challenge, derived from the concept of Tahaddi al-Burhan, meaning the ultimate test or challenge. Under Fremen law, leadership of a sietch could be contested through personal combat, with the challenger and the incumbent fighting to the death with crysknives. Paul Atreides faced such a challenge from Stilgar's people when he first entered Fremen society, and later from Feyd-Rautha Harkonnen in the climactic duel for the Imperial throne. The challenge embodied the Fremen principle that authority must be earned and maintained through demonstrated strength.