The Ajuran Sultanate (Saldanadda Ajuuraan, سلطنة الأجورانية), also natively referred-to as Ajuuraan, and often simply Ajuran, was a Somali Empire in the Middle Ages in the Horn of Africa that dominated the trade in the northern Indian ocean. They belonged to the Somali Muslim sultanate that ruled over large parts of the Horn of Africa in the Middle Ages. Through a strong centralized administration and an aggressive military stance towards invaders, the Ajuran Empire successfully resisted an Oromo incursion from the west and a Portuguese incursion from the east during the Gaal Madow and the Ajuran-Portuguese wars. Trading routes dating from the ancient and early medieval periods of Somali maritime enterprise were strengthened or re-established, and foreign trade and commerce in the coastal provinces flourished with ships sailing to and coming from many kingdoms and empires in East Asia, South Asia, Europe, the Near East, North Africa and East Africa.
The empire left an extensive architectural legacy, being one of the major medieval Somali powers engaged in castle and fortress building. Many of the ruined fortifications dotting the landscapes of southern Somalia today are attributed to the Ajuran Empire's engineers, including a number of the pillar tomb fields, necropolises and ruined cities built in that era. During the Ajuran period, many regions and people in the southern part of the Horn of Africa converted to Islam because of the theocratic nature of the government. The royal family, the House of Garen, expanded its territories and established its hegemonic rule through a skillful combination of warfare, trade linkages and alliances.
In the fifteenth century, for example, the Ajuran Empire was the only hydraulic empire in Africa. As a water dynasty, the Ajuran state monopolized the water resources of the Shebelle and Jubba rivers. Through hydraulic engineering, it constructed many of the limestone wells and cisterns of the state that remain in use today.