The High Caliphate
The High Caliphate was the zenith of Arab political power. A dark curtain had shrouded Persia's history after the Arab conquests destroyed the Sassanid Empire, and for a century the Persians sank into shocked despair. Despite the fiscal reforms of 'Umar II and Hisham, the Umayyad caliphate remained an Arab kingdom. Most scholars list 'Umar, Mu'awiya, and 'Abd al-Malik among the caliphs regarded as the founding fathers of Islamic government. Al-Ma'mun deserves a high rank among the 'Abbasid caliphs, even though his rise to power resulted from a bloody civil war that almost wiped out Baghdad. The building of Baghdad was part of a public works policy by which the 'Abbasids kept thousands of their subjects employed and their immense wealth circulating. Finally Baghdad was captured in 945 by a Shi'ite dynasty called the Buyids, and the 'Abbasids ceased to be masters even in their own house.