"The Shura [council] of the Islamic State met and discussed this issue [of the caliphate] ... The Islamic State decided to establish an Islamic caliphate and to designate a caliph for the state of the Muslims," said ISIS spokesman Abu Mohammad al-Adnani.
"The jihadist cleric Baghdadi was designated the caliph of the Muslims," said Adnani.
Baghdadi "has accepted this allegiance and has thus become the leader for Muslims everywhere."
"The words 'Iraq' and 'the Levant' have been removed from the name of the Islamic State in official papers and documents," Adnani said, describing the caliphate as "the dream in all the Muslims’ hearts" and "the hope of all jihadists."
Ever since the Prophet Muhammad’s death, a caliph was designated "the prince" or emir "of the believers.”
Source: Al Arabiya