"The new self-proclaimed caliph seeks to draw legitimacy by claiming heritage from the prophet's Quraysh tribe -- as did all IS leaders before him. 'The Qurashi name is used as a branding for the leader,' Hans-Jakob Schindler, director of the Counter-Extremism Project think-tank, told AFP. 'Even if it is just a made up name... it is sufficient for the network to function.'"