A caliphate is an Islamic state ruled by a single political and religious leader, or Caliph.
Caliphs are regarded by their followers as successors to the Prophet Muhammad and the leader of all Muslims.
The word “caliph” comes from the Arabic khalifa, meaning “successor”. Its use means the IS claims Baghdadi as the only legitimate successor to the Prophet.
First caliphate came into being after Prophet Muhammad’s death in 632. In the centuries which followed, caliphates had dominion in the Middle East and North Africa.
Historically, caliphates involved governance under Islamic law, with the leadership elected according to Sunni practice and selected from a group of Imams under Shia traditions.
Laws under a caliphate are traditionally defined in accordance with Islamic ethics. In the past the role of caliph has largely been symbolic, leaving the day-to-day running of government down to the devolved powers of local rulers.
The last widely accepted caliphate was abolished in 1924 by Turkish leader Kemal Ataturk after the collapse of the Ottoman Empire. Abdulmecid II was the last ruler of a caliphate.
In 2014, Islamist militant group ISIS has declared caliphate in parts of Iraq and Syria, appointing its leader, Abu Bakr al-Baghdadi, as Caliph.