The Qarmatian invasion of Iraq was a large-scale raid by the Qarmatians of Bahrayn against the Abbasid Caliphate's metropolitan region of Iraq, that began in autumn of 927 and continued until the summer of 928. The invasion was the culmination of a series of destructive raids against the Hajj caravans, and the sack of Basra and Kufa, during the previous years. Coming amidst a general political malaise in the Abbasid government, which appeared helpless to counter the Qarmatians, these attacks exacerbated the political tensions in Baghdad, leading to the downfall and execution of the vizier Ibn al-Furat. In October/November 927, the Qarmatian leader, Abu Tahir al-Jannabi, led a force of no more than 2,300 men to invade Iraq. In December, the Qarmatians captured Kufa and routed the much larger army of the semi-autonomous emir of Adharbayjan, Yusuf ibn Abi'l-Saj, who was captured. The Qarmatians then began to advance north along the Euphrates towards Baghdad, where a widespread panic broke out. An army of over 40,000 men was assembled to meet the threat, but the Abbasid commanders, Mu'nis al-Muzaffar and Abu'l-Hayja al-Hamdani, preferred to avoid combat and instead obstruct the Qarmatian advance by destroying the bridges and canals near the Abbasid capital. The resulting flooding brought the Qarmatian advance to a halt at the outskirts of the city on 7 January 928. The Qarmatians then withdrew again across the Euphrates and marched up the river into Upper Mesopotamia, plundering the region and securing ransom from its cities. Unopposed, the Qarmatians withdrew to their homes in the summer of 928. Their presence had led to uprisings by sympathizers, the so-called Baqliyya, in the Sawad of Kufa, but these were suppressed by the Abbasid authorities. The survivors of these uprisings joined the Qarmatians in their retreat to Bahrayn. In the aftermath of the invasion, the Qarmatians sacked Mecca on January 930 and captured Oman in the same year, but internal troubles halted their advance. A young Persian who had been taken prisoner in Iraq was recognized as the Mahdi by Abu Tahir, and power passed to him. His erratic behaviour, however, quickly made clear that he was not the millennialist figure expected by the Qarmatians, and he was murdered. The event demoralized the Qarmatians, who after that sought peaceful relations with the Abbasids. Nevertheless, the invasion of 927–928 severely deteriorated the financial and political situation in the Abbasid Caliphate, which descended into a vicious circle of military coups and internecine warfare among warlords, culminating in 946 with the takeover of Iraq by the Buyid dynasty. (en)