Muhammad did not formally appoint a successor, or khalifa in Arabic, and no clear replacement arose to lead the Muslim community forward at the time of his death. In fact, the umma divided into three groups, with each willing to appoint their own successor to the Prophet. Emerging as a vocal leader at this critical juncture, ‘Umar, one of Muhammad’s closest companions, convinced the majlis, or elders of the community, to elect Abu Bakr by consensus as a compromise candidate. Abu Bakr had been Muhammad’s closest friend; Muhammad’s marriage of political alliance to ‘A’isha, Abu Bakr’s daughter, further solidified their relationship.
The election of Abu Bakr (632 – 634) brought much-needed stability and an almost democratic form of government to Islam. As caliph, Abu Bakr held together the converts to Islam by deploying the forces at his disposal, thus cementing his authority among the Arabian tribes. He prevented any rebellious Muslim tribes from reverting to the worship of their traditional tribal gods, as they were wont to do. Abu Bakr died in 634, two years after the Prophet Muhammad had died.
The majlis chose ‘Umar (634 – 644), a close friend of Abu Bakr, to be the next caliph. ‘Umar had been the military power behind Abu Bakr. A dynamic and uncompromising leader, ‘Umar recognized the necessity of expansion northward to achieve various ends. First, he sought to subdue the security threat of raiding nomads, many of which remained a law unto themselves. Second, in his struggle to contain discontent, he used the cohesive element of jihad to unite the Muslim community against unbelievers and expand God’s dominion. (The Arabic term of jihad actually refers to a “struggle,” usually against spiritual impurity, often known as “greater jihad,” and is associated with fulfilling God’s objectives here on earth. The “lesser jihad,” alternatively, is a physical struggle against the unbelievers of the Dar al-Harb, or Abode of War, until it is absorbed into the Dar al-Islam, or Abode of Islam, where believers were free to practice their faith as members of the predominant faith. Of note is the fact that Muhammad did not consider jihad important enough to make one of the pillars of Islam.) Third, ‘Umar understood the importance of plunder for the nascent caliphate. Troops received four-fifths of the loot from conquest; the remainder of the revenue went to him to be dispersed amongst the neediest members in the Islamic community.
‘Umar directed the full might of Islam northward against the Eastern Roman Empire, sometimes referred to as the Byzantine Empire. In 634, their first encounter took place in southern Palestine. The ensuing Battle of Ajnadayn was a decisive victory for the Muslims and a major loss for Emperor Heraclius. Two years later, an outnumbered Muslim army defeated the Eastern Roman Empire yet again at the Battle of Yarmouk, located on the eponymous river, somewhere between Damascus and Jerusalem. In both instances, the Byzantines relied on their slow, heavy cavalry, whereas the Arabs capitalized on their light armor and their superior mobility. The Muslims realized that they could not just charge the East Roman lines; they showed their tactical superiority by flanking the Byzantines and executing a successful rearguard action instead. These victories opened up greater Syria to Muslim conquest. Antioch, Aleppo, and Jerusalem fell to the Muslims not long thereafter. ‘Umar appointed Mu‘awiya, a member of the Meccan Umayyad aristocracy to govern Syria at his behest.
Once he dealt with the increasingly vulnerable Byzantines in the Levant, ‘Umar directed his army to the east against the Sasanian Empire of Persia. In 636, fighting along the banks of the Euphrates River, a smaller Arab force triumphed over the Persians, at the Battle of Qadisiya. After successive days of exhaustive combat, the Muslims took advantage of environmental conditions and their light cavalry’s mobility when they chased a dust storm and took the Sasanids by surprise.
To save their empire, the Persians mounted a failed counterattack. In 642, Umar’s army eventually defeated the forces of the Sasanian Emperor Yazdagird III at the Battle of Nahavand, situated deep in Iran’s Zagros Mountains. Yazdagird fled to the east as a fugitive, and, in 651, met his death at the hands of a local miller who killed the emperor in order to rob him of his belongings.
In 639, General ‘Amr petitioned ‘Umar for permission to invade Egypt and eventually persuaded the caliph that he could easily take Egypt so gained his reluctant consent. In 641, he received a message from ‘Umar recalling his forces. The general ignored the order and seized Egypt with just a few hundred soldiers. With promises of toleration, ‘Amr convinced the Egyptian Coptic majority to side with him against the Greek Orthodox ruling minority, whose Patriarch Cyrus had been actively persecuting the Copts as followers of a Christian heresy that failed to recognize the Holy Trinity.
Clearly outnumbered Muslim armies thus successfully defeated two long-standing empires in the span of just a few decades. Several explanations help us understand the rapid expansion of Islam during this period. One concept, termed the vacuum theory, posits that the Byzantine and Persian empires had been severely weakened from near-continuous fighting, dating back decades prior to the rise of Islam, so they both suffered from the fatigue of war. Islam, therefore, occupied the vacuum of political power resulting from the collapse of these two exhausted empires.
The success of Muslim military strategy offers a second explanation. While Byzantine forces adopted a defensive stance on the battlefield, the Arabs employed more aggressive tactics, making use of their mobile light cavalry against their enemies’ heavily armored armies. Once victorious, the Arabs populated garrison cities on the frontier, called amsar, with Muslims. These military settlements provided security, served as logistical loci, and discouraged Muslim troops from mingling with the locals. The caliphs thereby prevented their warriors being assimilated into the communities of the conquered while also preventing soldiers from disturbing the peace. Fustat in Egypt, as well as Kufa and Basra in Iraq, were the largest of the amsar. From bases like these, the Arabs could expand and consolidate their hold over the frontier.
Religion also provided an impetus for the expansion of Islam. Fearing that internal tribal divisions threatened the early Islamic state, ‘Umar united the Muslims through their common Islamic theology and faced them against a common enemy. Dedicated to the expansion of Islam, Muslims used the concept of jihad as a way to unify the umma, or Islamic community, against a foreign foe. Faith motivated the troops, who were zealous and determined to fight.
Simple economics also served as a primary motivating factor in the expansion of Islam. For one, Muslim rulers applied the jizya, an annual tax levied on non-Muslims, to newly-conquered lands. The money derived from conquest functioned as a driving force in the growth of the caliphate. With the expectation of material reward, soldiers could earn money for their service. While the practice of dividing the spoils of war amongst the soldiers continued under ‘Umar, he also started offering salaries to his troops, determining salaries according to the length of service.
The Muslims further exploited the internal divisions of targeted societies, as exemplified in Egypt, where the Coptic Christian majority, together with a large Jewish minority in Alexandria, had suffered under the rule of an oppressive Greek Orthodox Christian minority but gained autonomy and toleration within an Islamic state. And in Syria, another monophysite Christian minority called the Syrian Orthodox Church, or Jacobites, collaborated with the Muslims and hastened the collapse of the Byzantines. All these factors led the early Islamic state to expand exponentially.
In 644, an Iranian captive from the Persian campaign stabbed ‘Umar to death. His successor, ‘Uthman (644 – 656), was an elderly man from the Umayyad Clan who won a contentious election over ‘Ali. ‘Ali possessed all of the ‘Alid bona fides. ‘Ali was not only son of Muhammad’s early protector, Abu Thalib; he was also the Prophet’s cousin and son-in-law. He had married Muhammad’s daughter Fatima; together, they had two sons, Hasan and Husayn. ‘Ali had also earned a well-deserved reputation as a virtuous Muslim. One of the first converts to Islam, he had journeyed with Muhammad on most of his expeditions and fought against the Meccans. Finally, ‘Ali also served as a valued advisor to the early caliphs on questions of dogma.
Two factions formed in the wake of questions over ‘Uthman’s succession, thus initiating the development of a division within Islam. One faction was a group of ‘Alids who believed that ‘Ali should inherit the mantle of Islam and referred to traditions suggesting that Muhammad had proclaimed to the faithful that ‘Ali should be his successor. The amsar followed the ‘Alids and later adopted the Shi‘a appellation. The other faction, the Umayyads contended that the method of appointing successors should be by consensus, as was done with the first caliphs. Mostly based in Mecca, they later identified as Sunnis. Over time, these factional differences became increasingly difficult to bridge.
Although ‘Uthman, one of the Prophet’s first converts, was a pious Muslim, he was a corrupt administrator. He displayed nepotistic tendencies that gave precedence to the Meccan elite, a practice that diverged from ‘Umar’s policies of favoring soldiers who had been the first to respond to the call to action. ‘Umar’s beneficiaries had usually originated from lesser tribes, those too weak to constitute a coherent threat to the establishment; by contrast, ‘Uthman’s appointees were members of the Meccan elite who generally pursued policies benefiting the Umayyad merchants of Mecca.
Government also began to disintegrate under ‘Uthman’s rule, as opposition and instability plagued his tenure as caliph. He managed to offend three separate groups of Muslims. The first of these were the older, pious Muslims, who hailed from Medina. They resented how the hated Umayyads had taken over the same umma that they had previously persecuted and had once tried to destroy. Second were the Quran reciters. When ‘Uthman commissioned and authorized a single official version of the holy text, an act for which he received many accolades, the Quran reciters lost the opportunity for gainful employment. Third were a disgruntled contingent of ‘Alids who called for ‘Uthman to resign and advocated the election of ‘Ali. Their discontent culminated in 656, when resentful devotees of ‘Ali from Egypt broke into ‘Uthman’s home in Medina and assassinated him, purportedly while he was reading the Quran. They then hastily arranged for the election of ‘Ali as ‘Uthman’s successor.
Thrice rejected by the majlis in favor of the first three caliphs, ‘Ali (656 – 661) reluctantly accepted the position of leader of the Islamic community. His selection represented a victory for the faction of legitimists disappointed in the earlier choice of ‘Uthman. ‘Ali assumed the role of caliph amid high expectations, for he was a pious and generous man. Yet the caliphate suffered under his rule. During this time of instability, he constantly had to suppress revolts. For example, tensions between the supporters of ‘Ali and the family of ‘Uthman eventually erupted into the first civil war in Islam. In 656, at the Battle of the Camel, ‘Ali engaged the combined forces of the Prophet’s favored wife, ‘A’isha, and her associates, Talha and Zubayr, who were both relatives of ‘Uthman. Because ‘Ali had failed to bring the dead caliph’s assassins to justice; these three together demanded satisfaction for his death.
The conspirators challenged ‘Ali near the garrison city of Basra, in southern Iraq, before he had the chance to move the caliphate from Medina to the sympathetic military settlement of Kufa. A first, diplomacy seemed to prevail, as ‘Ali sought to avoid bloodshed by negotiating. He succeeded in convincing the three to lay down their arms; however, a group later known as Kharijis conspired to undermine their reconciliation and set fire to the tents in both camps in the dead of the night. Pandemonium ensued. Because of this single impetuous action, both parties thought the other side had flouted the agreement, committing a violation of trust. During the ensuing battle, ‘A’isha was pushed into the middle of the fray on the back of a camel, as was Arab custom. The supporters who rallied to her side were cut down, and ‘Ali emerged victorious from a very bloody battle. The repercussions of his victory reverberated across the Islamic world, as older Muslim men castigated ‘A’isha for her part in the conflict and suggested that women should not play a role in public life.
This threat was not the only one ‘Ali faced, for he also had to contend with Mu‘awiya, ‘Uthman’s cousin and former governor of Syria. Conspicuously absent from ‘Ali’s new administration, Mu‘awiya refused to pay homage to ‘Ali and asserted his own independence in Syria. He also echoed the accusations of ‘A’isha, Talha, and Zubayr, as members of Mu‘awiya’s Umayyad Clan had expressed dismay about the quick election of ‘Ali, and questions still lingered over the new caliph’s part in ‘Uthman’s death. ‘Ali’s failure to act against ‘Uthman’s assassins proved his culpability, Mu‘awiya and the Umayyads, and Mu‘awiya asserted the traditional Arab custom of exacting revenge on one’s enemies.
His conflict with ‘Ali culminated in 657 when they met at the Battle of Siffin, on the Euphrates River in northern Syria. After months of clashes, ‘Ali agreed to arbitration with Mu‘awiya. Still preferring negotiation over bloodshed, ‘Ali had been of the opinion that Muslims should never take up arms against fellow Muslims. His willingness to negotiate with Mu‘awiya, however, caused some of Ali’s own soldiers to defect and adopt the appellation of Kharijis, from kharaja, meaning “to depart.” The first sect in Islam, they departed from Ali because they believed that “judgement belongs to God alone” (Quran 6:57); they saw ‘Ali’s willingness to negotiate with Mu‘awiya as somehow reducing the role of God in determining a successor. In lieu of arbitration, they thought that God would determine the rightful successor by influencing the outcome on the field of battle.