That is why Abu Bakr insists on signing off all his communiqués with “al-Qurashi al-Hassani” (descendant of the Prophet's grandson, from the Quraysh clan of Mecca). Western journalists tend to drop both titles for sake of practicality, but for the Islamic State and its propaganda machine, they are essential to al-Baghdadi's legitimacy. When the last official Ottoman caliphate was abolished in 1924, Damascus Muslims created a Caliphate Society to headhunt for a suitable caliph, claiming that unless the job is immediately filled by a suitable candidate, a charlatan will emerge one day to assume the title for himself. That exactly is what Abu Bakr did eighty years later. He did not invent the idea. He simply tailored it to suit his political ambitions.