He was born in 532 AH, at a time when his father, Najm al-Dīn, was serving as deputy governor of Tikrit.

Duwayn is a small town on the border of Azerbaijan, facing Aran and al-Karaj; its inhabitants are Hadhbani Kurds.

He studied hadith with Abū Ṭāhir al-Salafī, the jurist ʿAlī ibn Bint Abī Saʿd, Abū al-Ṭāhir ibn ʿAwf, and al-Quṭb al-Naysābūrī, and he himself transmitted reports.

Nūr al-Dīn(1) appointed him and sent him with the army under his uncle, Asad al-Dīn Shīrkūh. When Shīrkūh gained control of Egypt he did not live long, so Ṣalāḥ al-Dīn succeeded him; the troops submitted to him, he subdued the Banū ʿUbayd, erased their state, and took possession of the Cairo palace with all the goods and rarities it contained, among them a single ruby weighing seventeen dirhams. The author of al-Kāmil, Ibn al-Athīr(2), says: “I saw it and weighed it.”

The palace was emptied of its people and treasures, and he proclaimed allegiance to the Abbasid caliphate.

He was eminently fitted for rule—impressive, courageous, decisive, a combatant in God’s cause, constantly on campaign, and lofty in aspiration. His reign lasted a little over twenty years.

He assumed power after Nūr al-Dīn, and his dominions expanded widely.

From the moment he became sultan he renounced wine and worldly pleasures. He built a wall around al-Qāhirah and Miṣr(3), and in 568 AH he dispatched his brother Shams al-Dīn, who captured Barqah, then