Iraq conflict: What does 'caliphate' mean?
Islamist militant group Isis has said it is establishing a caliphate, or Islamic state, on the territories it controls in Iraq and Syria.
Setting up a caliphate ruled by the strict Islamic law has long been a goal of many jihadists.
The BBC's Jeremy Bowen takes a closer look at the word, saying it harks back to the rise of Islam when the Prophet Muhammad's followers conquered vast territories in the Middle Ages.
First broadcast on BBC Radio 4's Today programme on Monday 30 June.
30 Jun 2014