Muhammad was born in 20 January 1082. He succeeded his nephew,
Malik Shah II, as Seljuq Sultan in
Baghdad, and thus was theoretically the head of the dynasty, although his brother
Ahmad Sanjar in
Khorasan held more practical power. Muhammad I probably allied himself with
Ridwan of
Aleppo in the
Battle of Khabur River against
Kilij Arslan I, the sultan of
Rüm, in 1107, in which the latter was defeated and killed. Following the internecine conflict with his half brother,
Berkyaruq, he was given the title of
malik and the provinces of Armenia and Azerbaijan. Dissatisfied by this he revolted again, but had to flee back to Armenia. By 1104, Berkyaruq, ill and tired of war, agreed to divide the sultanate with Muhammad. Muhammad became sole sultan following the death of Berkyaruq in 1105. In 1106, Muhammad conquered the
Ismaili fortress of
Shahdiz, and ordered the
Bavandid ruler
Shahriyar IV to participate in
his campaign against the Ismailis. Shahriyar, greatly angered by the message Muhammad sent him, refused to aid him against the Ismailis. Shortly after, Muhammad sent an army headed by Amir Chavli, who tried to capture
Sari but was unexpectedly defeated by an army under Shahriyar and his son
Qarin III. Muhammad then sent a letter, which requested Shahriyar to send one of his sons to the Seljuq court in
Isfahan. He sent his son
Ali I, who impressed Muhammad so much that he offered him his daughter in marriage, but Ali refused and told him to grant the honor to his brother and heir of the Bavand dynasty, Qarin III. Qarin III then went to the Isfahan court and married her. In 1106/1107,
Ahmad ibn Nizam al-Mulk, the son of the famous
vizier Nizam al-Mulk, went to the court of Muhammad I to file a complaint against the
rais (head) of
Hamadan. When Ahmad arrived to the court, Muhammad I appointed him as his vizier, replacing Sa'd al-Mulk Abu'l-Mahasen Abi, who had been recently executed on suspicion of heresy. The appointment was due mainly to the reputation of Ahmad's father. He was then given various titles which his father held (Qewam al-din, Sadr al-Islam and Nizam al-Mulk). Muhammad I, along with his vizier Ahmad, later campaigned in
Iraq, where they defeated and killed the
Mazyadid ruler Sayf al-dawla Sadaqa ibn Mansur, who bore the title "king of the Arabs". In 1109, Muhammad I sent Ahmad and Chavli Saqavu to capture the
Ismaili fortresses of
Alamut and Ostavand, but they failed to achieve any decisive result and withdrew. Ahmad was shortly replaced by Khatir al-Mulk Abu Mansur Maybudi as vizier of the Sejluq Empire. According to
Ali ibn al-Athir (a historian who lived about a hundred years later), Ahmad then retired to a private life in
Baghdad, but, according to the contemporary biographer,
Anushirvan ibn Khalid, Muhammad I had Ahmad imprisoned for ten years. Muhammad I died on 18 April 1118 and was succeeded by
Mahmud II, although after Muhammad I's death Sanjar was clearly the chief power in the Seljuq realms. ==Family==