Shaikh Hasan-i Buzurg 
Hasan Buzurg was married to Bagdad Katun the daughter of Amir Coban. Coban later became the most influential person at the court of Abu Sa'id Mirza. However, the Ilkhan soon became enamored with Bagdad Katun, and sought to have her divorce Hasan Buzurg. Coban sent the two of them to Qarabagh in an attempt to rid Bagdad Katun from Abu Sa'id's mind, but the effort failed, and Bagdad Katun was forced to marry the Ilkhan. After the murder of Coban in 1327, Bagdad Katun and the Grand Vizier Ghiyath al-Din Muhammad competed for influence over Abu Sa'id. Ghiyah al-Din spread a rumor that Bagdad Katun and Hasan Buzurg were plotting against the Ilkhan; Hasan Buzurg was arrested in 1332. His mother convinced the Ilkhan to spare his life, and he was imprisoned in the castle of Kamakh. In 1333, however, he was cleared and was sent to become governor of Rüm. During Abu Sa'id's lifetime, Hasan Buzurg was also called upon by Ghiyas al-Din to help stop rampant tax abuses in eastern Persia.
Following the death of Abu Sa'id, several parties competed for the Ilkhanid throne. In 1336 Hasan Buzurg saw his chance and raised a child, Muhammad Khan, to claim the position. On July 24 Hasan Buzurg and Muhammed met the forces of Musa Khan and 'Ali Padshah in the Ala-Tagh area; Musa was defeated and 'Ali Padshah killed. Hasan Buzurg pursued Musa on his way to Baghdad and created many losses for his enemy. He then proceeded to Tabriz, where he married the granddaughter of Coban and the wife of Abu Sa'id, Delsad Katun, who was pregnant with Abu Sa'id's daughter. Meanwhile, the amirs in Khurasan adopted their own candidate for Ilkhan, Togha Temur. Togha set off in 1337 to subdue western Persia. Azarbaijan and 'Iraq-i 'Ajam were taken. In March he arrived before Sultaniyeh, the former capital of the Ilkhans, and Hasan Buzurg withdrew to Arran. Musa's forces, initially battling Togha's, now joined the invader. Togha and Musa met Hasan Buzurg at Soghurlug in the Maragheh area on June 15; Hasan defeated them, took Musa prisoner shortly after, and executed him. Togha gave up the campaign and withdrew to eastern Persia.
Shortly afterwards, however, several descendants of Coban united under his grandson Hasan Kucek, who used a slave to impersonate his father in order to legitimatize his cause. The Chobanids battled with Hasan Buzurg on July 16, 1338 at Naushahr in the Alataq area. Hasan Buzurg was defeated; his puppet khan, Muhammed, was killed. Shortly afterwards, the Chobanids conquered Azarbaijan. A peace was declared, but Hasan Buzurg sought to be rid of the Chobanid threat. He offered the Ilkhanid throne to Togha Temur, who invaded early in 1339. Hasan Kucek, however, offered the hand of Sati Beg in marriage, and when Togha responded warmly to the proposal, he forwarded the letters to Hasan Buzurg. The latter, enraged, halted his expedition to support Togha, who was forced to withdraw during the summer of that year.
Following his abandonment of Togha Temur, Hasan Buzurg recognized Jahan Temur, a grandson of Geikhatu, as Ilkhan. The conflict with the Chobanids again boiled over, and Hasan Buzurg and Jahan Temur met Hasan Kucek and his new puppet Suleiman Khan in battle on the Jaghatu. There Hasan Buzurg was defeated on June 26, 1340. He fled to Baghdad; following which he declared Jahan Temur deposed. With the Chobanids continuing to press him, Hasan Buzurg again recognized Togha Temur’s suzerainty, and struck coins in his name. After he stopped recognizing Togha in 1344, he still did not proclaim himself independent, and ruled with the title of ulus beg, as a mere governor, simply leaving the Ilkhan throne unfilled. Nevertheless, this marks the beginning of effectively independent Jalayirid rule.
For the rest of his reign Hasan Buzurg attempted to deal with the Chobanids. He managed to form an alliance with Hasan Kucek’s uncle Surgan, as well as the governor of Diyarbakr and the Mamelukes, but Surgan was soon convinced to abandon the alliance, and the Mamelukes withdrew shortly after. He also offered assistance to another of Hasan Kucek’s uncles, Yagi Basti, as well as to Mas’ud Shah of the Injuids, in their attempt to expel Hasan Kucek’s cousin Pir Hosayn from Shiraz. The murder of Hasan Kucek in 1343 did not provide much relief, for his brother Malek Asraf sent an army to conquer Baghdad in 1347. Jalayirid forces, however, inflicted heavy losses on the force, which was forced to retreat by the summer. While Malek Asraf and the Chobanids would survive until 1357, their threat to the Jalayirids was diminished. Hasan Buzurg continued to play an influential part in Persian politics; he assisted the Injuid Abu Ishaq against the Muzaffarids, helping him restore his rule in Isfahan in 1353. The latter, however, destroyed the Injuids in 1357.
Hasan Buzurg died in 1356. He was succeeded by his son, Shaikh Uvais. In addition to Uvais, he was the father of Amir Zahid.
Hasan Buzurg seemed intent on restoring unity to the Ilkhanate. This is evidenced by the fact that he used the title of ulus beg all of his life, and raised several men as Ilkhans instead of ruling in his own name. Furthermore, he attempted to unify Persia; he had sent a Muhammad-I Mulai to act as governor of Khurasan, for example; the latter was later executed by Togha Temur’s military commander Arghun Shah. In attempting to maintain the Ilkhanate, he ultimately failed, and in some ways accelerated its disintegration, by preventing other forces such as the Chobanids from gaining more influence. However, he set up a strong state that would rule over Iraq and parts of Persia for over half a century, a state that would become even more powerful under his successor Shaikh Uvais.
Hasan Buzurg is also remembered for his friendship with Shaikh Saf'i al-Din (d. 1334) of the Ardabil order. Saf'i al-Din's descendents would found the Safavid dynasty of Persia, and later on many of Hasan Buzurg's accomplishments would be accredited to his friendship with the Shaikh. After Hasan Buzurg's death, the Jalayirids continued to maintain good relations with the Arbadil order.
- Peter Jackson (1986). The Cambridge History of Iran, Volume Six: The Timurid and Safavid Periods. ISBN 0-521-20094-6
- Charles Melville and 'Abbas Zaryab. http://www.iranica.com/articles/search/searchpdf.isc?ReqStrPDFPath=/home1/iranica/articles/v5_articles/chobanids&OptStrLogFile=/home/iranica/public_html/logs/pdfdownload.html