a branch of the Oghuz Turks (Turkmen originally from the area of the Syr Darya). The name “Seljuk” comes from Seljuk, a tribal leader of the Oghuz Turks in the tenth and early 11th centuries; it is also a name for the Muslim dynasty—the Seljukids—created by the Seljuks.

In the 1030’s the Seljuks received lands in Khorasan as vassals of the Ghaznavid state; they subsequently rebelled against the Ghaznavids, defeating them at Dendenkan in 1040. Under Togrul (Tughrul) Beg, who adopted the title of sultan during his reign (1038–63), the Seljuks overran Kwarazm and nearly all of Iran in the 1040’s and Azerbaijan, Kurdistan, and Iraq in the 1050’s. In 1055 they took Baghdad. Under Alp Arslan (1063–72), the Seljuks conquered Armenia in 1064 and defeated the Byzantines at Manzikert in 1071. Between 1071 and 1081 they conquered Asia Minor and other lands. Under Sultan Malik Shah (1072–92), the Seljuk state reached its zenith, subjugating Georgia and the Middle Asian Karakhanid state as well.

The military-nomadic elite of the Oghuz and other Turkic tribes evolved into a feudal elite, holding vast areas as military fiefs, or iqtas, and betraying aspirations toward political decentralization. The sultans came to draw their support primarily from the Iranian civil bureaucracy, which had a vested interest in a strong central authority, an interest expressed, among others, by Nizam al-Mulk.

However, feudal fragmentation continued to gather momentum in the Seljuk state. During the reign of Malik Shah, several sultanates emerged, ruled by lateral branches of the Seljukid dynasty but only nominally dependent on the central authority, the Great Seljuk—namely, the sultanates of Kerman (1041–1187), Rum (in Asia Minor, 1077–1307), and Syria (1094–1117). After the First Crusade (1096–99) the Seljuks first lost Palestine and then Syria, the coastal regions of Asia Minor, and Georgia. After the death of Malik Shah, the Ismailian movement only compounded the internecine strife among the feudal rulers.

In 1118 the Seljuk state was partitioned among the sons of Malik Shah. Sanjar received the eastern regions, with the capital at Merv; Muhammad received western Iran and Iraq, an area known as the Seljuk Sultanate of Iraq (1118–94). Sanjar (also Sinjar; ruled 1118–57) waged a struggle against the powerful and virtually independent feudal lords of the outlying areas. Defeated by the Karakatai, he lost his supremacy over Middle Asia in 1141. In 1153 the Balkh Oghuz defeated him, and the Oghuz plundered Merv, Nishapur, Tus, and other cities in Khorasan.

After Sanjar died in 1157, the power of the Great Seljukids came to an end in Khorasan. After 30 years of internecine feudal strife, the shahs of Khwarazm won supremacy over Khorasan, Kerman, and western Iran. The Seljuks retained only the Sultanate of Konya.