Abū al-ʿAbbās Aḥmad ibn al-Hasan al-Mustaḍīʾ (Arabic: أبو العباس أحمد بن الحسن المستضيء), better known by his laqab al-Nāṣir li-Dīn Allāh (الناصر لدين الله; 6 August 1158 – 5 October 1225) or simply as al-Nasir, was the Abbasid caliph in Baghdad from 1180 until his death.

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.

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.

In response, some medieval historians write that al-Nasir appealed to Genghis Khan, the rising Mongol chief, to check Muhammad's progress.

The steppes of Central Asia were set in motion by Genghis Khan, and his hordes put to flight the Khwarizm Shah, who died an exile in an island of the Caspian.

This conflict possibly prevented Toghrul III and Qizil Arslan from aiding Muhammad b. Bahram Shah, the last Seljuk Sultan of Kirman, who had been driven from Kirman by Oghuz rebels driven out from Khurasan in 1186 The rebel army consisted of the forces of the Amirs of Zenjan and Maragha, the retainers of both Kamal Ai-Aba, head of the Mamluks, and of Saif al-Din Rus, husband of Innach Khatun, while Toghrul himself received significant support from Turkmens,[10] and their combined army forced Qizil Arslan to leave Hamadan after some clashes.

[11] Toghrul undertook two diplomatic ventures in 1187, he journeyed to Mazandaran to request aid from Bavandid Husam al-Daula Ardashir, and received troops from him, and Toghrul also sent messages to al-Nasir, asking him to restore the palace of the Seljuk Sultan in Baghdad for him, but the Caliph razed the palace and then sent aid to Qizil Arslan, who agreed to become the Caliph's vassal.

[11] Qizil Arslan had declared Sanjar b. Suleiman-Shah as the Seljuk Sultan of Iraq, and reinforced by troops sent by the Caliph now invaded Hamadan, Toghrul, unable to resist the invasion, first retreated to Isphahan,[13] then to Urmia.

[12] He was joined by an army led by his brother in law Hasan Kipchiq, and Toghrul also tried to get help from the Ayyubids and the Caliph, even sent his infant son as hostage to Baghdad in a futile gesture.

[15] His nephews began to rule independently, and one of the Mamluks of Jahan Pahalvan, Mahmud Anas Oglu,[16] freed Toghrul III from his prison in May 1192.

Toghrul occupied Hamadan, secured the treasury and came to rule over Isphahan and Jibal, but did not attempt to negotiate an agreement with Abu Bakr, against Qutlug Innach.

Toghrul felt threatened with the presence of a hostile force in Rey, which was a strategic town commanding communication with Jibal and Azerbaijan was unacceptable to the Sultan.

Ala ad-Din Tekish sent Toghrul's head to al-Nasir who displayed it at the Nubi Gate in front of his palace, while his body was hanged at Rey.