Jalāl al-Dawla Mu‘izz al-Dīn Abu’l-Fath Malik Shāh I was the third Great Saljûq sultan (1072-1092), under whom the power of the sultanate reached its greatest extent.
A son of Sultan Alp Arslān, Malik Shāh was appointed as his father’s heir in 1066. After his father’s death (1072), he was accepted as sole ruler by defeating his paternal uncle Qāwurd, who had challenged him for supreme authority. He also had to put down two rebellions by his brother Tekish in 1081 and 1084, but thereafter his rule was secure. Malik Shāh’s power was founded on two principal pillars: the central administration headed by his father’s Persian vizier, Nizām al-Mulk, and his large standing army of Turkish slave soldiers. Many of the more far-flung parts of the empire were granted to members of the Saljûq family as princes or governors. In the east of the empire, Malik Shāh carried on wars against the Ghaznawids and Qarakhānids, and in the west against Georgia, Byzantium, and the Fātimid caliphate. He appointed his brother Tutush (I) as ruler of southern Syria and Palestine (1078), but as the Turkish conquest of northern Syria proceeded, MalikShāh later installed governors of his own choosing in Aleppo, Antioch, and elsewhere.
The first signs of instability in Saljûq rule began to appear when Nizām al-Mulk was assassinated (October 1092). Malik Shāh’s relationship with the ‘Abbāsid caliph in Baghdad, who had originally legitimized the rule of the Saljûqs, deteriorated toward the end of the reign. It is possible that the sultan intended to depose the caliph, but he died while hunting in November 1092, in circumstances that are still disputed by historians.
Whether or not the sultan was murdered like his vizier, the deaths of its two most powerful men within such a short period plunged the Great Saljûq Empire into disarray. Malik Shāh’s widow Terken Khātan had her young son Mahmûd proclaimed sultan by the caliph, but this move was contested by another son, Barkyāraq, and by Tutush in Syria. The ensuing civil wars, which continued into the twelfth century, greatly limited the ability of the Great Saljûqs to respond effectively to the threat to Muslim Syria and Palestine that was presented by the First Crusade (1096-1099).