Militant Islamist fighters ride horses as they take part in a military parade along the streets of Raqqa, northern Syria, 30 June 2014
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Iraq crisis: What is a caliphate? In 90 seconds

20 August 2014 Last updated at 09:20 BST

Islamic State forces have captured large parts of northern Iraq in recent weeks, having declared a caliphate in parts of Iraq and Syria in June.

But just what is a caliphate? BBC News explains - in 90 seconds.

Video produced by Michael Hirst