IS militants paraded through Raqqa after the "caliphate" was proclaimed in June ... there and renamed it Raqqa ("the marsh"). In 771, the Abbasid Caliph al-Mansour chose Raqqa to serve as a ...

Inside the Abbasid palace of Baghdad, built in around 12th century. The caliphates (Islamic states) were governed by a caliph. They were the successors to Muhammad. The first major caliphate was ...