Hasan ibn Buya

Rukn al-Dawla
Coin of Rukn al-Dawla
Buyid Emir of Jibal
Reign	935 – September 976
Successor	Fakhr al-Dawla (in Ray) Mu'ayyad al-Dawla (in Hamadan)
Born	898 Daylam
Died	September 976 Ray
Issue	Fakhr al-Dawla 'Adud al-Dawla Mu'ayyad al-Dawla
Father	Buya
Religion	Shia Islam

Hasan (died September 976), better known by his laqab as Rukn al-Dawla (Persian: رکن‌الدوله دیلمی), was the first Buyid amir of northern and central Iran (c. 935-976). He was the son of Buya.

Hasan was the son of Buya, a Dailamite fisherman from Lahijan, who left his Zoroastrian faith and converted to Islam. Ahmad had an older brother named 'Ali and a younger brother named Ahmad. He also had a sister named Kama.

In around 928, Hasan's brother 'Ali joined the services of Makan, who was the Samanid governor of Ray. 'Ali then managed to gain military positions for Hasan and their other brother Ahmad. At the time, Hasan was about thirty years old. When Makan attacked his Samanid overlords and was subsequently defeated by the Ziyarid prince Mardavij, the brothers transferred their allegiance to the latter.

In the following years, 'Ali repudiated his subservience to Mardavij and, after some time, managed to create an empire in Fars. During this time, Hasan distinguished himself in the battles over that province. Mardavij, however, marched south and forced 'Ali to recognize his authority in around 934. Hasan was sent to Madavij's court as a hostage. The death of Mardavij in 935 allowed Hasan to escape, and also provided an opportunity for the Buyids to expand into central Iran. 'Ali therefore sent Hasan to take Isfahan. The Ziyarids, now under Vushmgir, were busy dealing with the Samanids, allowing the Buyid to easily take the city. This success did not last, however. Internal disruptions, combined with an invasion by Vushmgir, forced Hasan to abandon Isfahan to the Ziyarids three years later. In 940, he appointed Abu 'l-Fadl ibn al-'Amid as his vizier.