Umayyad Frontiers and Fortified Landscapes

The Umayyads ruled a caliphate, a Muslim state headed by a caliph, from Damascus between 661 and 750. Their frontiers met the Byzantine, or Eastern Roman, Empire in Anatolia, extended through Khorasan in northeastern Iran and neighboring lands, and reached across North Africa. After 756, a branch of the dynasty governed al-Andalus, the Muslim-ruled parts of the Iberian Peninsula, first as a polity ruled by an emir, a title for a Muslim ruler, and from 929 to 1031 as a caliphate. Its northern marches linked provincial towns and local authorities to Córdoba. These regional systems relied on different combinations of garrisons, tribute collected by local rulers and fortified administrative districts.

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Passes and garrisons on the Byzantine frontier

The Taurus and Anti-Taurus ranges in modern southern Turkey marked the land boundary between Muslim-held Syria and Byzantine Anatolia. The Cilician Gates, a pass through the Taurus north of Tarsus, channelled travel between the Syrian plain and the Anatolian plateau. In 703, the Umayyad commander ʿAbd Allāh ibn ʿAbd al-Malik retook Mopsuestia, the ancient city at modern Misis, and rebuilt its citadel on older foundations. In 704, a garrison including 300 selected soldiers was installed there. The ninth-century historian al-Baladhuri says the church inside the fortress became a granary and that troops from Antioch wintered at Mopsuestia before returning to campaign. Reusing a fortified city and converting a church to storage made the post a place to house soldiers and hold provisions through the winter.

Umayyad forces did not establish lasting rule west of the Taurus. The failed siege of Constantinople in 717–718 ended the dynasty’s last attempt to take the imperial capital; by the early eighth century the Taurus ranges formed the main boundary between the two states. Across the Taurus, armies operated against Byzantine territories in campaigns seeking passage beyond the mountain frontier.

Local rulers and garrisons in Khorasan

Khorasan included the former Sasanian province, part of the Sasanian Iranian Empire, as well as lands toward Tokharistan and beyond the Oxus River, in modern northeastern Iran, Afghanistan, Turkmenistan and Uzbekistan. In the early conquests, Arab forces commonly negotiated agreements with rulers of major towns. Those rulers often kept their positions, collected agreed annual tribute through existing tax arrangements and paid it in money or goods. The caliphal government therefore received resources through local administrations as well as through its own soldiers.

Merv, in present-day Turkmenistan, was a principal Arab garrison and a base for operations farther east. The governor Qutayba ibn Muslim, appointed in 705, led campaigns into Sogdia, the region north of the Oxus that includes parts of modern Uzbekistan and Tajikistan. He negotiated agreements with local rulers and also used local forces in campaigns. When rulers withheld tribute or rebelled, governors faced renewed campaigns to restore their authority. In this eastern setting, the garrison at Merv and negotiated arrangements with regional rulers were complementary means of maintaining Umayyad power.

Kairouan and the North African network

Ifriqiya, the early Islamic province centered on modern Tunisia and eastern Algeria, contained both inherited Byzantine towns and new Arab foundations. In 670, the commander ʿUqba ibn Nāfiʿ founded Kairouan in central Tunisia as a miṣr, a garrison settlement and base for his forces. It became the inland provincial capital. After Carthage was captured in 698, Tunis grew as a new harbor city, connecting the government to coastal routes. These foundations grew alongside older urban centers rather than replacing the entire inherited network.

Arab authorities also used fortified towns such as Béja and Gabès, reoccupying or adapting existing defenses. In Corisande Fenwick’s reconstruction from later Arabic accounts, Kairouan’s founder assigned plots to tribal groups and established a congregational mosque and governor’s residence. Under Caliph Hisham (724–743), governor Bishr ibn Safwan repaired the mosque, laid out markets along its main street and built fifteen water reservoirs. Kairouan remained the province’s chief troop-assembly point until the Kharijite troubles of 122–123 AH (740–741).

Marches and fortresses in al-Andalus

From Córdoba, the Umayyads governed northern al-Andalus through thughūr, or frontier districts commonly called marches. The Upper March centered on Zaragoza and the Ebro valley, the Middle March on Toledo and later Medinaceli, and the Lower March on Mérida. The Middle March’s center shifted from Toledo toward Medinaceli by the tenth century. These regional districts linked towns and surrounding territory to the Cordoban government through administration and military posts.

The Banū Qāsī, a powerful local family that converted to Islam, held authority in the Upper March. Musa ibn Musa governed from Tudela in 850 and became governor of Zaragoza in 852, bringing a member of the family into the administration of the march’s principal city.

Tortosa, in northeastern Spain near the Ebro’s outlet to the Mediterranean, illustrates how frontier building changed over time. Archaeologist Joan Negre’s study identifies early fortified spaces in the emirate period with the ribāṭ, a frontier institution combining religious service with armed defense. Under the caliphate, state fortresses in the district also served as military posts and places for collecting taxes. Those combined functions connected the Cordoban government to a northern territory through both garrisons and revenue.