Muhammad I Tapar

Muhammad I Tapar fought his way to the Seljuk throne through a long civil war and then spent his sole rule trying to repair what the war had broken. A son of Malik-Shah I, he was governor of Ganja in the northwest when he rose against his half-brother Berkyaruq in 1099, drawing on the support of his full brother Sanjar, who held Khorasan. Five battles and repeated reversals later, the brothers partitioned the empire in 1104; Berkyaruq's death in early 1105 then delivered the whole western sultanate to Muhammad, who set aside his rival's infant heir and was recognized in Baghdad.

As sultan he proved the most energetic of Malik-Shah's sons. His most sustained campaign was against the Nizari Assassins, whose power had grown unchecked through the civil war years. In 1107 he took Shahdiz, their fortress overlooking Isfahan, killing its commander Ahmad ibn Attash, and in his final years he kept Alamut itself under nearly continuous pressure, with a siege in progress when he died. Against the Crusader states he organized the first serious counteroffensives from the Seljuk heartland, dispatching repeated expeditions under Mawdud of Mosul between 1110 and 1113. The campaigns achieved little durable — Syrian emirs distrusted eastern armies almost as much as Franks, and Mawdud was murdered in Damascus — but they marked the sultanate's return to the Syrian theater it had abandoned in the 1090s.

Muhammad also presided over the consolidation of the atabeg system, granting provinces to Turkish commanders as guardians for Seljuk princes; the arrangement kept order in his lifetime and bred hereditary dynasties after it. He died in Isfahan in April 1118, about thirty-six years old, leaving the western sultanate to his young son Mahmud II. Real seniority in the dynasty passed instead to his brother Sanjar in Khorasan, who defeated Mahmud within months and reduced the western line to dependency. Muhammad Tapar was the last ruler to hold the Great Seljuk west as a genuinely governing sultan rather than a name in the khutba.