But al-Mamun's victory was followed by a relatively peaceful reign. In Egypt the Copts, after expressing their individuality by several risings against their Moslem overlords, were them- selves converted to Islam.
In 829 al-Mamun visited Syria and made a fresh survey of its lands with a view to increasing the revenue from it. Four years later he visited Damascus to test the judges there and enforce his decree that any judge who did not subscribe to the Mutazilite view of the creation of the Koran could not hold office. Several of his predecessors had visited Syria on their way to the pilgrimage or to battle against the Byzan- tines. They were all kept fully informed by their governors and postmasters, who doubled as chiefs of secret police.
Another brother, al-Mutasim (833-842), succeeded al- Mamun and moved the capital to Samarra. It was he who, in 838, led a victorious expedition against Amorium, the last incursion into Anatolia before a long period of peace on Syria's northern border. Palestine was the scene of a major revolt during his reign. In 840 a Yemenite Arab who always wore a veil in public raised the white Umayyad banner and attracted a large but undisciplined following among the peasants. A thousand Abbasid troops readily took him captive and dispersed his men.
The quiet which prevailed under al-Mutasim's son al- Wathiq was shattered under his brother al-Mutawakkil (847- 861). In 850 and 854 he revived the discriminatory legisla- tion against members of tolerated sects and supplemented it by new features which were the most stringent ever issued against the minorities. Christians and Jews were enjoined to affix wooden images of devils to their houses, level their graves even with the ground, wear outer garments of yellow and ride only on mules and asses with wooden saddles marked by two pomegranate-like balls on the cantle. Violent outbreaks took place in Damascus (854) and Horns (855), with both Christians and Moslems participating. The people of Damascus killed their Abbasid governor and were
