Muʿizz al-Dīn (Abū al-Ḥusayn) Muḥammad Kart, Ghiyāth al-Dīn’s third son, ruled the Kartid state from 24 Ramażān 732/19 June 1332 to 5 Dhū al-Qaʿda 771/31 May 1370. Despite youthful mistakes, he built on his father’s foundations. Following the death of the last Il-Khan, Abū Saʿīd Bahādur Khān (13 Rabīʿ II 736/30 November 1335), the Kartids became one of the independent Persian kingdoms that established themselves from Balkh to Āzarbayjān and the Persian Gulf, the most prominent being Jalayirids (Īlkā or Ilkanid), Qara-Qoyunlu (and later, Aq-Qoyunlu), Sarbadarids, and Muzaffarids.

Ṭaghā-Temür (d. 754/1353), the nominal Il-Khan—or “Chinggisid pretender” as Charles Melville put it—was elected at a congress held in 737/1336 at Sulṭān-Maydān (in the Nishapur Quarter). He involved himself in the post-Ilkhanate struggles transpiring in western Persia. The absence of Ṭaghā-Temür’s armies, and his vizier’s exactions, fostered a rebellion in the Bayhaq district of Nishapur Quarter. Tax rebels morphed into the Sarbadarid dynasty. This confessionally mixed band allied with Shaykh Ḥasan Jūrī (d. 742/1342), a charismatic “Sufi” of indeterminable Shiʿi proclivities. The joint forces marched on Herat but were defeated. They remained a menace until Muʿizz al-Dīn established détente with their leader, Khwājah ʿAlī Muʾayyad (r. 764–83/1363–81).

Muʿizz al-Dīn came to rule his domains like an old-fashioned Persian Padishah. By this I mean that he tried to hew to idealized Persian concepts of kingship as articulated in pre-Islamic literature as The Letter of Tansar; and post-Islamic mirrors for princes. On, for instance, the restoration of faith, where “a man of true and upright judgment” was needed “when corruption became rife and men ceased to submit to Religion, Reason and the State, and all sense of values disappeared,” are ideals reflected in the Kartid’s proclamation of independence dated 19 JumādáI 750/5 August 1349, and his letters to Sultan Muḥammad b. Tughluq-Shāh (r. 724–52/1324–51) of the Delhi Sultanate.

The economy flourished because of Muʿizz al-Dīn’s engagement with agricultural and hydrological policies: “[a king] will bring to pass that which concerns the advance of civilization, such as constructing underground channels, digging main canals, building bridges […], rehabilitating villages and farms […].”