From Wikipedia, the free encyclopedia

The Battle of the Zab took place on the banks of the Great Zab river in what is now Iraq on January 25, 750. It spelled the end of the Umayyad Caliphate and the rise of the Abbasids, a dynasty that would last (under various influences and with varying power) until the 13th century.

A serious rebellion had broken out in 747 against the Umayyad dynasty, who ruled much of the Middle East from 661 to 750. The main factor which incited this rebellion was that to the outlying peoples of the Caliphate, the Umayyads (based in Damascus) seemed distant, and the governors they appointed to rule were essentially corrupt and obsessed only with their own gain. Equally, the Umayyads could claim no direct descent from Muhammad, however the Abbasids could make such a claim — a fact they played upon greatly during the revolution, although not specifying until the revolution had been won that they were in fact descended from Muhammad's uncle (see the Abbasid and Umayyad pages for more details).

In 750, the army of the Umayyad caliph Marwan II fought a combined force of Persians, Shi'ite Arabs and Abbasid soldiers at the Zab. Marwan's army was, on paper at least, far larger and more formidable than that of his opponents, as it contained many veterans of the Ummayyads' earlier campaigns against the Byzantine Empire, but its support for the caliph was only lukewarm. It is fair to say their morale had been damaged — whereas the Abbasid's armies had been increased — by the series of defeats inflicted on the Umayyads earlier in the rebellion.

The Abbasid army formed a spear wall, a tactic they had adopted from their Syrian opponents, presumably from witnessing it in earlier battles. This entailed standing in a battle line with their lances pointed at the enemy (similar to the stakes used by English longbowmen at Agincourt and Crécy many centuries later). The Umayyad cavalry charged, possibly believing that with their experience they could break the spear wall. This, however, was a mistake on their part and they were all but butchered. The Umayyad army fell into retreat, its morale finally shattered. Many were cut down by the zealous Abbasids or were drowned in the wintertime River Zab.

Marwan himself escaped the battlefield and fled down the Levant, pursued relentlessly by the Abbasids, who met no serious resistance from the Syrians because the land had recently been laid waste by an earthquake and pestilence. Marwan fled at last to Busir, which is a small town on the Egyptian Nile delta. It was here, a few months after the battle, that he was at last killed in a short battle and replaced as caliph by Abu al-Abbas as-Saffah, bringing to an end Umayyad rule in the Middle East.

• "The Court of the Caliphs- when Baghdad ruled the Muslim world" by Hugh Kennedy