Abbasid Caliphate

On 13 February 1258, Hulegu Khan ordered the sack of Baghdad. The caliph had called him young and ignorant. What followed was one of the most concentrated episodes of killing and destruction in human history.

On 25 January 750, the Abbasid rebels crushed the Umayyad Caliphate at the Battle of the Zab and then killed almost every member of the ruling dynasty. Almost. One prince swam a river and didn't look back — and built medieval Spain.