Seljuk Frontiers and Fortifications

From the eleventh to the thirteenth century, Seljuk power reached across very different borderlands: the Great Seljuk realm in Iran and Central Asia, the Caucasus, the mountain region between the Black and Caspian Seas, and the sultanate of Rum in Anatolia, the Asian part of modern Turkey. A frontier was rarely a single line. Sultans held some towns directly, relied on allied or tributary rulers elsewhere, and could dispatch mobile field forces when local arrangements failed. A garrison was a force stationed in a fort or town; its reach depended on roads, food supplies and cooperation beyond the walls.

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Eastern rule through appointed and allied rulers

Great Seljuk authority in the east joined direct rule to layers of subordinate government. Khorasan, a region centered on cities such as Merv in present-day Turkmenistan and Nishapur in northeastern Iran, was assigned to Sanjar by his half-brother as his province. At first Sanjar ruled as a subordinate sultan under an atabeg, a senior guardian and adviser. Transoxiana, the lands beyond the Oxus River around Bukhara and Samarkand in present-day Uzbekistan, lay farther from the court. The Qarakhanids, a Central Asian ruling house, governed there while acknowledging Seljuk overlordship. An overlord claimed obedience, tribute or military help without replacing every local ruler.

Sanjar sometimes used that local dynasty to make Seljuk authority stick. After capturing a Qarakhanid ruler who had invaded Khorasan, he installed a prince of the same defeated house who was also related to the Seljuks. The appointment tied local legitimacy to the sultan’s backing. This arrangement could hold while the sultan could intervene, but the defeat at Qatwan in 1141 changed the balance: the Qara Khitai, a Khitan-led power that had moved west from East Asia, defeated Sanjar and his Qarakhanid allies near Samarkand, and Transoxiana passed out of Khorasan’s control. Sanjar restored his rule in Khorasan through campaigns by 1143.

Pastoral groups, whose livelihoods depended on moving herds between seasonal pastures, also crossed these jurisdictions. Oghuz Turkmen groups arriving from the steppe defeated and captured Sanjar near Balkh in 1153. Khorasan then fragmented: some Oghuz leaders took over towns, while other groups pillaged across the province. The episode shows why an imperial claim or a chain of fortified towns could not by itself manage mobile forces and their demands on settled regions.

Ani and the mountain approaches

The Caucasus and Armenian highlands had their own kingdoms, fortified cities and narrow routes. Ani, near modern Kars in eastern Turkey, stood on an important route between Anatolia and the Caucasus. When Great Seljuk sultan Alp Arslan’s army besieged it in 1064, Ani was held by Byzantine and Armenian defenders. The Byzantine Empire was the eastern Roman state centered at Constantinople. Ani fell after twenty-five days.

Ani’s defenses used the ground and the wall plan together. The city had two rings of walls, an outer ditch and seven gates. The gates in the inner and outer walls did not line up. An attacker who crossed the first gateway therefore had to turn and move between the walls before reaching the next; this made it harder to bring a battering ram, a heavy beam used to break gates, straight against an inner entrance. The plateau and ravine added natural protection, while Ani’s position connected its walls to the wider Silk Road routes.

Who controlled Ani changed as alliances shifted. After the Seljuk capture, the Shaddadids, a Kurdish-origin dynasty that ruled parts of the Caucasus, governed Ani under Seljuk overlordship; an inscription names Sultan Malik-Shah as the overlord of the Shaddadid ruler Manuçehr. In 1124 the city surrendered to King David IV of Georgia, and its ruler Abu’l-Aswar II was taken captive. A Shaddadid prince retook Ani in 1126. Later, Georgian and Muslim coalitions fought over the city: the Seljuk atabeg Ildegoz recaptured it in 1164 and handed it to a Shaddadid prince, before the Georgians took it again in 1174. The walls guarded a major route, but authority over the people and the surrounding region moved among neighboring rulers.

Rum’s western frontier and its local powers

In western Anatolia, the early sultans negotiated with Byzantium while Turkmen pastoral groups ranged farther into the frontier. Around 1081, the Byzantine emperor Alexios I and the Rum ruler Suleiman agreed to use the River Drakon as a border, intended to keep Bithynia, in northwestern Anatolia, and the Bosphorus strait beside Constantinople free of Turkish forces. Over the following century, however, the sultans had limited control over Turkmen groups seeking pasture near the Byzantine border. An agreement between courts could set expectations without turning every valley into a guarded boundary.

Further east and south, Rum rulers dealt with Armenian Cilicia, the Armenian kingdom on the southeastern Mediterranean coast, and competing Turkish dynasties as well as Byzantium. In the early twelfth century, Masud of Rum initially acknowledged the Danishmendid ruler Ghazi as his overlord, a stronger ruler to whom he owed allegiance, and married Ghazi’s daughter. After the Danishmendid succession became disputed, Masud used alliances with local princes to strengthen his own position; one ruler of Malatya became his subordinate. These relationships shifted the balance around towns such as Sivas and Kayseri without requiring the sultan to replace every local dynasty at once.

Fortresses could also change hands as part of a negotiated settlement. After the Byzantine emperor Manuel I was defeated at Myriocephalon in 1176, he received generous terms from Rum sultan Kilij Arslan II and surrendered only some frontier strongholds. The outcome secured Seljuk gains while leaving an imperial power on the other side of the frontier. Control of a pass or fortress was therefore one part of a relationship that could also involve truces, tribute and local rulers.

Ports joined coastal walls to inland routes

For the sultans of Rum, access to the sea depended on defending a port and keeping its overland connections open. Antalya on the Mediterranean became the sultanate’s first major port in 1207. Sinop on the Black Sea was captured in 1214; a route from the port reached inland to Sivas, connecting Anatolia to the northern Black Sea trade. These coastal towns gave the sultans access to shipping, but they also needed garrisons, repaired walls and officials able to manage local populations.

The siege of Sinop shows how a port could be taken through military pressure and negotiation. Historian Mesut Çıtak’s study of the thirteenth-century chronicler Ibn Bibi describes Seljuk commanders consulting people familiar with Sinop. They judged a direct assault unlikely to work and recommended cutting off aid by land and sea. One account summarized in the study credits a commander named Behram with using one thousand men to block aid arriving by water. After the city surrendered, its ruler Kir Alexios was released on terms of allegiance, annual tribute and military support when required. Seljuk authorities assigned a governor, Hetum, an Armenian official familiar with the local community, and appointed guards. Fifteen emirs, or senior military officials, who had joined the campaign contributed to repairs of cracks in the walls and towers. Taking a port thus meant arranging both its military defense and its local government.

At Alanya, the former fortress of Kalonoros was taken from its Armenian lord around 1221 and renamed after Rum sultan Kayqubad. The Kızıl Kule, completed in 1226, guarded the harbor and the shipyard being built beside it. The shipyard, completed in 1228, was used to build and repair ships and to make sails and other equipment. The castle also received strengthened walls and new cisterns, which stored water for its population and garrison. Together, the tower, shipyard, water storage and road links made the harbor a defended base rather than an isolated coastal prize.