Belonging to the leading tribe of the Oghuz Turk group, the Seljuks adopted Islam in around 960 under the tribal leader Seljuk; they were initially in the service of the Qarakhanids of Transoxiana. Seljuk's grandsons, Tughril (1038-1063) and Chaghri (1038-1060), divided the territory into a western half (later Isfahan) and an eastern half (Merv). Following his victory over the Ghaznavids (1040 at Dandanqan), the elder Tughril extended the empire to the west, conquered Persia, parts of Anatolia, and Iraq after 1042, and replaced the Buyids as protector of the caliph in Baghdad in 1055 (becoming an honorary caliph and a sultan). The political and cultural zenith of the Seljuks came with the overall rulers Alp Arslan (1060/63-1072) and Malik Shah (1072-1092), as well as their prominent vizier, Nizam Al-Mulk (1060/65-1092), who enforced Sinicism as the state religion with the help of the Madrasa system. In 1064 the Seljuks occupied Armenia, gained sovereignty over Mecca in 1070, defeated Byzantium in 1071 at Malazgirt, and conquered the Arab Peninsula.

Signs of disintegration began to emerge after 1092, due to a power struggle between pretenders, and a new empire finally emerged under Sultan Mahmud (1105-1118) with a subsequent division. A weakening regime in the west (Iran/Iraq) existed until 1194, while a final period of prosperity came under Sultan Sanjar in the east (1118-1157). Finding itself constantly harassed by its neighbors from 1135 onwards, the eastern empire fell to Turkish tribes and Khwarazm-Shahs in 1157 and the remainder of the western empire also to the Khwarazm-Shahs in 1194. Breakaway dynasties resulted in the Shaybanids' own branches in Kerman (1041-1187 main capital Bardashir) and Syria (1094-1117 main capitals: Damascus and Aleppo), as well as the Anatolian Seljuks.

Rulers of Great Seljuk

History of Iran
Toğrül bin Mikail (Tughril Beg) 1037-1063
Alp Arslan bin Chaghri 1063-1072
Jalal ad-Dawlah Malik Shah I 1072-1092
Nasir ad-Din Mahmud I 1092-1094
Rukn ad-Din Barkiyaruq 1094-1105
Mu'izz ad-Din Ahmed Sanjar 1097-1157
Mu'izz ad-Din Malik Shah II 1105
Ghiyath ad-Din Mehmed I Tapar (Muhammad) 1105-1118
Mahmud II 1118-1131
Dawud (David) 1131-1132
Toğrül II (Tughril Beg) 1132-1134
Mas'ud 1134-1152
Malik Shah III 1152-1153
Mehmed II (Muhammad II) 1153-1160
Süleyman Shah (Sulaiman Shah) 1160-1161
Arslan Shah 1161-1176
Toğrül III (Tughril Beg III) 1176-1194