Muhammad II ibn Mahmud (1128–1159) was Sultan of Seljuq Empire from 1153 to 1159. He was son of Mahmud II and brother of Malik-Shah III. The Cambridge History of Iran notes that Sultan Muhammad "tried energetically to restore the slipping authority of his dynasty in Iraq,"

He was raised in Fars along with his brother Malik-Shah III. In 1148, their uncle Sultan Ghiyath ad-Din Mas'ud, who had no heirs and was in a weak position, appointed Malik-Shah III as heir, and gave his daughter in marriage to him. On 13 September 1152, Mas'ud died at Hamadan, and Malik-Shah III ascended the throne. In 1153, Muhammad, who was then in Khuzestan, marched towards Iraq and deposed his brother Malik-Shah III from the Seljuq throne, and ascended the throne himself. Meanwhile, the insurgent Abbasids under caliph al-Muqtafi was seizing the Turks of Iraq, and in 1155 supported a rival claimant to the throne, Suleiman-Shah. Furthermore, al-Muqtafi also sent an army to conquer Jibal, but the army was defeated by Muhammad. In 1157, Muhammad marched to the Abbasid capital of Baghdad with an army of 30,000 men, while his ally the Zangid Qutb ad-Din Mawdud marched from Mosul to capture the Caliphate's provinces in Central Iraq. On January 12, Muhammad reached the walls of western Baghdad.

In response the Caliph gathered all his troops from Hillah and Wasit to defend the capital. In February, unable to defend western Baghdad, the caliph abandoned the western side and ordered all the bridges over the Tigris river, which separates the western side of Baghdad from its eastern side, to be destroyed. Muhammad crossed to the western side and easily captured it, and established his camp while at the same time the caliph fortified the walls of eastern Baghdad. Several catapults and ballistas were installed on the city's walls. The caliph also armed the natives of Baghdad by giving them armour and weapons, and incited them to fight the enemy of the caliphate, whom he called infidels since they waged war against the caliph, the successor of the prophet and the leader of the ummah. He also ordered his vizier Awn ad-Din ibn Hubayra to give 5 golden dinars to every wounded soldier.

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