Abū al-ʿAbbās Aḥmad ibn al-Hasan al-Mustaḍīʾ (), better known by his al-Nāṣir li-Dīn Allāh (; 6 August 1158 – 5 October 1225) or simply as al-Nasir, was the Abbasid caliph in Baghdad from 1180 until his death. His literally can mean The One who Gives Victory to the Religion of God. He continued the efforts of his grandfather al-Muqtafi in restoring the caliphate to its ancient dominant role and achieved a surprising amount of success as his army even conquered parts of Iran. According to the historian, Angelika Hartmann, al-Nasir was the last effective Abbasid caliph. In addition to his military success al-Nasir built many monuments in Baghdad that are still standing such as Zumurrud Khatun Mosque and Mausoleum. Biography Al-Nasir was the son of Caliph al-Mustadi and a Turkish umm walad called Zumurrud (Emerald). His reign was unusual for the rise of the futuwwa groups in his reign, connected to Baghdad's long-standing ayyarun. These urban social groups had long existed in Baghdad and elsewhere, and they were often involved in urban conflicts, especially sectarian riots. Al-Nasir made them into an instrument of his government, reorganizing them along Sufi lines and ideology. In the early years of his caliphate, his goal was to crush the Seljuq power and replace it with his own. He incited rebellion against the Seljuq Sultan of Persia, Toghrul III. The Khwarezm Shah, Ala ad-Din Tekish, at his instigation, attacked the Seljuq forces, and defeated them in 1194; Toghrul was killed and his head exposed in the caliph's palace. Tekish, recognized now as supreme ruler of the East, bestowed on the caliph certain provinces of Persia that had been held by the Seljuqs. Al-Nasir's mother Zumurrud died in December 1202–January 1203, or January–February 1203, and was buried in her own mausoleum in Sheikh Maarouf Cemetery. Her mausoleum is known as Zumurrud Khatun Mausoleum. Al-Nasir sent his vizier to Tekish with some gifts, but the vizier irritated Tekish, who attacked the caliph's troops and routed them. Thereafter hostile relations prevailed for many years. The Caliph assassinated a governor of Tekish by using an Ismaili emissary. Tekish responded by having the body of al-Nasir's vizier, who died on a campaign against him, exhumed, and the head stuck up at Khwarizm. Irritated at this and other hostile acts, the Caliph retaliated by treating with indignity the pilgrims who came from the East under Khwarizm's flag. But beyond such poor