Abbasid civil war (865–866)
The Abbasid civil war of 865–866, sometimes known as the Fifth Fitna, was an armed conflict during the "Anarchy at Samarra" between the rival caliphs al-Musta'in and al-Mu'tazz, fought to determine who would gain control over the Abbasid Caliphate. The war, which lasted for about a year, largely revolved around a prolonged siege of Baghdad and ended with al-Mu'tazz as sole caliph. Al-Musta'in was abandoned by his supporters and forced to abdicate; in spite of a guarantee that his life would be spared, he was executed shortly afterward.
The outcome of the war was a major victory for the Turkic military establishment, which had been responsible for al-Mu'tazz's rise to power, and allowed the Turks to maintain their effective power over the government and military of the caliphate. The partisans of al-Musta'in, namely the Tahirid family, the Arab military factions, and the citizens of Baghdad, continued to be excluded from the politics of the central government after their surrender, although they were allowed to keep the positions they had before the war. Central Iraq, where most of the fighting took place, was devastated by the activities of both sides.
The historian al-Tabari provided a lengthy and detailed account of the war. Other Muslim historians, such as al-Mas'udi and al-Ya'qubi, also mentioned the war in their works.
Background
The caliph al-Mutawakkil had created a plan of succession that would allow his sons to inherit the caliphate after his death; he would be succeeded first by his eldest son, al-Muntasir, then by al-Mu'tazz and third by al-Mu'ayyad. In 861 al-Mutawakkil was assassinated by a group of Turkish military officers, likely with the support of al-Muntasir. During al-Muntasir's short reign, the Turks pressured him into removing al-Mu'tazz and al-Mu'ayyad from the succession. When al-Muntasir died, the Turkish officers gathered together and decided to install the dead caliph's cousin al-Musta'in on the throne. The new caliph was almost immediately faced with a large riot in Samarra in support of the disenfranchised al-Mu'tazz; the rioters were put down by the military but casualties on both sides were heavy. Al-Musta'in, worried that al-Mu'tazz or al-Mua'yyad could press their claims to the caliphate, first attempted to buy them off and then threw them in prison.After the suppression of al-Mu'tazz's supporters, the caliph's reign continued largely unabated until 865. The continual inability of the government to pay the soldiers, however, combined with infighting among the ranks of the Turks, threatened the stability of the regime. At the beginning of 865, a quarrel among the Turkish officers broke out, and the general soldiery quickly became involved. When one of the officers was killed, the soldiers turned violent, and soon they were rioting throughout the streets of Samarra. Faced with this hostile situation, al-Musta'in and two of the senior Turkish officers, Wasif and Bugha al-Sharabi, decided to leave Samarra for Baghdad, where they were arrived in the first week of February 865. Upon their arrival, they were greeted by the city's powerful Tahirid governor, Muhammad b. 'Abdallah, in whose palace the caliph took up his residence.
When the Turks in Samarra realized that al-Musta'in had departed from the city, they cut off traffic to Baghdad. A delegation of Turks then went to see the caliph; when they arrived, they asked for forgiveness for their actions and for the caliph to return with them to Samarra. Al-Musta'in, while promising the Turks that they would continue to be paid, refused to leave Baghdad, and he and Muhammad b. 'Abdallah mocked them for their perceived insolence. The humiliated Turks angrily returned to Samarra and told their compatriots what had happened; they then decided to depose al-Musta'in. The soldiers released al-Mu'tazz from his prison and acknowledged him as their caliph. Al-Mu'tazz agreed to the proposal and an oath of allegiance was drawn up; many of the officials in Samarra then swore allegiance to him.
Beginning of hostilities
With two members of the Abbasid dynasty now claiming to be caliph, war became inevitable. On al-Musta'in's side, Muhammad b. 'Abdallah quickly took command of the military effort. He ordered that all food shipments from Baghdad to Samarra be halted, and instructed allies in the Mosul region to do the same. Letters were sent by Muhammad to friendly commanders calling on them to mobilize their forces, and a recruitment drive was initiated in Baghdad. In preparation for a siege, the city was fortified, with the work being completed by February 22. The bridges and canals around al-Anbar were destroyed, flooding the area and hindering any possible enemy troop movements there. Muhammad also wrote to the tax officials throughout the empire, instructing them that their revenues were to be sent to Baghdad instead of Samarra.For his part, al-Mu'tazz wrote to Muhammad, urging him to declare allegiance to him. Soon after, al-Mu'tazz put his brother Abu Ahmad in command of an army and instructed him to fight against al-Musta'in and Muhammad. The army, consisting of five thousand Turkish and Ferghanan soldiers under the leadership of Kalbatikin al-Turki and two thousand North African soldiers under the leadership of Muhammad b. Rashid al-Maghribi, departed Samarra on February 24. Six days later they arrived in Ukbara, where Abu Ahmad led the prayers in the name of al-Mu'tazz. The Turks and North Africans began looting the area between Ubkara and Baghdad, causing many of the local residents to abandon their estates and fields. On March 10, Abu Ahmad and his army appeared before the Shammasiyah gate on the East side of Baghdad, and the siege of the city began.
Strategies and military strength
Al-Musta'in
Neither caliph participated in the direct military operations of the war. In Al-Musta'in's case, he was generally content to leave the responsibility of conducting the war effort to Muhammad b. 'Abdallah. As commander, Muhammad opted for an overall defensive strategy. Relying on his position in Baghdad, he was reluctant to engage in any sort of offensive operations outside the city and its surrounding districts, even when he was advised by others to do so. While he did make an effort to securing the nearby towns that controlled access to the city, there is no mention of any attempt to attack Samarra. By staying within Baghdad and keeping the city's supply routes open, while at the same time cutting off foodstuffs and tax receipts meant for Samarra, Muhammad likely believed that he could outlast al-Mu'tazz's armies.A massive amount of work was done to prepare Baghdad for a siege. Walls and trenches were constructed on both the east and west sides of the city, at a cost of over three hundred thousand dinars. Ballistas and mangonels were installed on the walls, and "war engines" designed to hinder enemy movement were placed in front of the city gates. The market awnings were removed so as to prevent them from being set on fire, and the areas outside the city were ploughed so that the mud would entrap the attackers. A few days after the fighting began, Muhammad ordered the razing of a large area behind the walls, so that the defenders would have more room to operate in.
Muhammad had numerous sources of manpower in his allies and in the people of Baghdad. He could rely on many friendly military commanders to heed his call for assistance, and in the early months of the war several small regiments from Iraq, the Jazira, the Jibal, the Arab-Byzantine frontier and elsewhere arrived in Baghdad. Muhammad also had an ally in his nephew Muhammad b. Tahir, who was the governor of most of the eastern provinces, although at the time the latter was largely preoccupied with the rebellion of Hasan b. Zayd in Tabaristan. In order to augment the ranks of his soldiers, Muhammad instituted a draft in Baghdad and called on for volunteers to serve al-Musta'in. A group of Khorasani pilgrims en route to Mecca at the time the war began were asked to stay and fight. Many of the city's brigands were also recruited and provided with weapons. At first they were given mats to protect themselves and bags of rocks or bricks to attack the enemy with; later they were given clubs, placed under their own chief and registered in the military roll so that they could be paid. Arab Bedouins and Kurdish tribesmen from the surrounding regions also fought for al-Musta'in.
In keeping with normal Abbasid court practice, gifts were routinely bestowed upon officers and soldiers by both al-Musta'in and Muhammad. Tabari's narrative of events contains numerous instances of commanders being rewarded for their service. They were given gifts on a number of occasions, such as their initial arrival in Baghdad with their troops, distinguishing themselves on the battlefield, or being selected to lead an important mission. Traditional robes of honor were regularly given out; other gifts included jewelry, ceremonial swords, money, and increased allotments for the troops.
The exact size of the army under Muhammad's command is not explicitly stated, but it was likely much greater than al-Mu'tazz's forces. As many of his units were irregulars, however, their conduct in battle was not always reliable, and they were disciplined often for their failure to follow orders. In addition, while many army commanders were willing to pledge themselves to al-Musta'in's cause, not all of them were willing to take orders from Muhammad; there are multiple instances of pro-Musta'in regiments outside Baghdad acting independently and engaging the Turks on their own initiative.
Al-Mu'tazz
From the start of the crisis, al-Mu'tazz was concerned with portraying himself as the legitimate caliph. He had been proclaimed as heir-apparent during his father's lifetime, and according to the succession arrangements he should have become caliph after the death of al-Muntasir. When he had signed away his rights to the caliphate in 862, he had been under duress to do so, with the Turks threatening to kill him if he refused, and therefore he considered the deed of abdication to be void. He also sought to convince the people that they could switch their allegiance to him without breaking the oath they had taken to serve al-Musta'in, and went through the effort to explain in detail how this could be done in a letter to Muhammad b. 'Abdallah.Al-Mu'tazz was initially accommodating toward those in Samarra who opposed his bid for the caliphate, and did not compel anyone to swear the oath to him if they refused to do so. He did, however, write to commanders stationed throughout the empire requesting their support, and soon reinforcements were arriving in Samarra. As the conflict progressed, he steadily gained followers as members of al-Musta'in's camp began to defect to him. He also made efforts to entice al-Musta'in's officers, writing offers to them and promising substantial rewards if they would switch their allegiance to him.
Al-Mu'tazz's brother Abu Ahmad was put in charge of the Samarran forces at the beginning of the war. He was charged by the caliph with defeating al-Musta'in and Muhammad b. 'Abdallah, and was given the authority to command the army in any manner he pleased. Abu Ahmad's overall strategy was to keep Baghdad under constant attack from his troops, and to gain the surrender of the city by either assaulting it or starving its inhabitants until they lost the will to fight any longer. Toward this end, al-Mu'tazz sent armies to secure the neighboring towns that controlled access to Baghdad, and Abu Ahmad attempted to halt and seize any revenue shipments heading toward the city. The way in which Abu Ahmad ran the siege was not unquestionably accepted by al-Mu'tazz, who reportedly wrote him a letter in the middle of the war complaining of his lack of progress in forcing al-Musta'in's capitulation, but he remained in command of the main besieging force throughout the entire conflict.
Al Muwaffaq/Abu Ahmad's army at the beginning of the siege numbered approximately 7,000 soldiers, including 5,000 Turkic and Fergan troops under command of Kilbutqin and 2,000 North African troops. Additional troops sent from Samarra a short time later increased its size to 11,000, though a large number of the reinforcements were killed soon after their arrival. At a later point in the war, a spy for Muhammad b. 'Abdallah reported that the besieging armies on the East and West sides of Baghdad totaled 19,000 men, and that al-Mu'tazz had very few additional troops to put in the field, since Samarra had been almost completely emptied of soldiers.