The spirit of conquest under ʿUmar I

Abū Bakr’s successor in Medina, ʿUmar I (ruled 634–644), had not so much to stimulate conquest as to organize and channel it. He chose as leaders skillful managers experienced in trade and commerce as well as warfare and imbued with an ideology that provided their activities with a cosmic significance. The total numbers involved in the initial conquests may have been relatively small, perhaps less than 50,000, divided into numerous shifting groups. Yet few actions took place without any sanction from the Medinan government or one of its appointed commanders. The fighters, or muqātilah, could generally accomplish much more with Medina’s support than without. ʿUmar, one of Muhammad’s earliest and staunchest supporters, had quickly developed an administrative system of manifestly superior effectiveness. He defined the ummah as a continually expansive polity managed by a new ruling elite, which included successful military commanders like Khālid ibn al-Walīd. Even after the conquests ended, this sense of expansiveness continued to be expressed in the way Muslims divided the world into their own zone, the Dār al-Islām, and the zone into which they could and should expand, the Dār al-Ḥarb, the abode of war. The norms of ʿUmar’s new elite were supplied by Islam as it was then understood. Taken together, Muhammad’s revelations from God and his Sunnah (precedent-setting example) defined the cultic and personal practices that distinguished Muslims from others: prayer, fasting, pilgrimage, charity, avoidance of pork and intoxicants, membership in one community centred at Mecca, and activism (jihad) on the community’s behalf.

Forging the link of activism with faithfulness

ʿUmar symbolized this conception of the ummah in two ways. He assumed an additional title, amīr al-muʾminīn (“commander of the faithful”), which linked organized activism with faithfulness (īmān), the earliest defining feature of the Muslim. He also adopted a lunar calendar that began with the emigration (Hijrah), the moment at which a group of individual followers of Muhammad had become an active social presence. Because booty was the ummah’s major resource, ʿUmar concentrated on ways to distribute and sustain it. He established a dīwān, or register, to pay all members of the ruling elite and the conquering forces, from Muhammad’s family on down, in order of entry into the ummah. The immovable booty was kept for the state. After the government’s fifth-share of the movable booty was reserved, the rest was distributed according to the dīwān. The muqātilah he stationed as an occupying army in garrisons (amṣār) constructed in locations strategic to further conquest: al-Fusṭāṭ in Egypt, Damascus in Syria, Kūfah and Basra in Iraq. The garrisons attracted indigenous population and initiated significant demographic changes, such as a population shift from northern to southern Iraq. They also inaugurated the rudiments of an “Islamic” daily life; each garrison was commanded by a caliphal appointee, responsible for setting aside an area for prayer, a mosque (masjid), named for the prostrations (sujūd) that had become a characteristic element in the five daily worship sessions (ṣalāts). There the fighters could hear God’s revelations to Muhammad recited by men trained in that emerging art. The most pious might commit the whole to memory. There too, the Friday midday ṣalāt could be performed communally, accompanied by an important educational device, the sermon (khuṭbah), through which the fighters could be instructed in the principles of the faith. The mosque fused the practical and the spiritual in a special way: because the Friday prayer included an expression of loyalty to the ruler, it could also provide an opportunity to declare rebellion.

The series of ongoing conquests that fueled this system had their most extensive phase under ʿUmar and his successor ʿUthmān ibn ʿAffān (ruled 644–656). Within 25 years Muslim Arab forces created the first empire to permanently link western Asia with the Mediterranean. Within another century Muslim conquerors surpassed the achievement of Alexander the Great, not only in the durability of their accomplishment but in its scope as well, reaching from the Iberian Peninsula to Central Asia. Resistance was generally slight and nondestructive, and conquest through capitulation was preferred to conquest by force. After Sāsānian Al-Ḥīrah fell in 633, a large Byzantine force was defeated in Syria, opening the way to the final conquest of Damascus in 636. The next year further gains were made in Sāsānian territory, especially at the Battle of al-Qādisiyyah, and in the next the focus returned to Syria and the taking of Jerusalem. By 640 Roman control in Syria was over, and by 641 the Sāsānians had lost all their territory west of the Zagros. During the years 642 to 646 Egypt was taken under the leadership of ʿAmr ibn al-ʿĀṣ, who soon began raids into what the Muslims called the Maghrib, the lands west of Egypt. Shortly thereafter, in the east, Persepolis fell; in 651 the defeat and assassination of the last Sāsānian emperor, Yazdegerd III, marked the end of the 400-year-old Sāsānian empire.