Question

give a brief account of the caliphs between the 8 and 12th century

Answer 1

Baghdad: 8th century

In their new city of Baghdad the Abbasid caliphs adopt the administrative system of the long-established Persian empire. Persian Muslims are as much involved in the life of this thriving place as Arab Muslims. Here Islam outgrows its Arab roots and becomes an international religion. Here the Arabic and early Persian languages coalesce to become, from the 10th century, what is now known as Persian - combining words from both sources and using the Arabic script. Here Mesopotamia briefly recovers its ancient status at the centre of one of the world's largest empires.

At no time is this more evident than in the reign of the best-known of the Abbasid caliphs, Harun al-Rashid.
From the 9th century the rule of the Abbasid caliphs in Baghdad is often, in many parts of the Muslim world, more nominal than real. In Palestine and Syria there are uprisings from supporters of the previous Umayyad dynasty, whose base was Damascus. In the rich province of Egypt, governors are increasingly unruly (as many as twenty-four are appointed and then dismissed during the 23-year caliphate of Harun al-Rashid).
Persian independence from Baghdad: 9th century

From about 866 the whole of eastern Persia, to Kabul in the north and Sind in the south, is gradually overrun by a Persian from a family of metal-workers; he is known as al-Saffar ('the coppersmith'), giving his short-lived dynasty the name of Saffarids. In 876 he is strong enough to march on Baghdad, though he is prevented from reaching it by the army of the caliph.

In 900 the Saffarids are defeated by another Persian dynasty, the Samanids. The new rulers are aristocrats, descended from a nobleman by the name of Saman Khudat. They preside over the first conscious revival of Persian culture since the Arab conquest. The slow end of the Abbasids: 10th - 16th century

There are times in the 10th century when the caliphs have little power outside the confines of Baghdad itself, but from the 11th century their prestige is to some degree restored. This is thanks to the Seljuk Turks, who recover a large empire and rule it from Baghdad - accepting the subordinate title of sultan and deferring to the caliphs as the superior religious authority.