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).

When Makan attacked his Samanid overlords and was subsequently defeated by the Ziyarid prince Mardavij, the brothers transferred their allegiance to the latter.

That same year, 945, saw Rukn al-Dawla expelled from all of central Iran by Ibn Muhtaj, the governor of Samanid Khurasan.

[5] Some time later, Abu Mansur Muhammad, a former Samanid general who had rebelled against them, took refuge in Ray, and was honored by Rukn al-Dawla, who, along with his brothers, greatly awarded him with riches.

He traveled to Shiraz and stayed there for at least nine months in order to secure his son's succession there, despite the fact that the Samanids were threatening his own possessions.

Marzuban's brother and the Sallarid ruler of Dailam, Wahsudan, shortly sent an army under the Kurdish general Daisam, but the latter was forced to retreat to Arran.

Furthermore, the vizier of Daisam, Ibn Mahmud, betrayed him and joined Abu Mansur, who managed to successfully conquer Azerbaijan, and was shortly appointed as the governor of the region by Rukn al-Dawla.

[8] However, an unnamed secretary of Abu Mansur, who had greatly helped him during his conquest of Azerbaijan, felt insulted that he had chosen Ibn Mahmud as his minister instead of him, and shortly raised an army, and joined Daisam.

The fight between the Buyids and the Ziyarids, along with their Samanid overlords over Gurgan and Tabaristan also continued until 955, with control of the provinces switching hands several times.

Rukn al-Dawla was forced to sign a treaty with the Samanids, in which he promised to respect the independence of the Ziyarids in exchange for peace.

The peace did not last long, however; in 958 Vushmgir occupied Ray for a short time, while in 960 Rukn al-Dawla briefly gained control of Gurgan.

In 966, a large group of ghazis from Khorasan, plundered Jibal, and also managed to wound Rukn al-Dawla's vizier Abu 'l-Fadl.

The ghazis shortly marched towards an important Buyid library in Ray, which was, however, saved by Abu 'l-Fadl's chief librarian Ibn Miskawayh.

Abu 'l-Fadl shortly urged Rukn al-Dawla to depose Ibrahim and impose direct Buyid control on the region.

[12] In 970, Rukn al-Dawla sent Abu 'l-Fadl on an expedition against the Kurdish ruler Hasanwayh, who, however, died before he managed to deal with the latter.

[11] During the same period, Rukn al-Dawla's fighting with his rivals began to work in his favor, and he was able to sign a less humiliating treaty with the Samanids in 971 or 972, though he continued to pay tribute.

In terms of a capital, Isfahan at first served Rukn al-Dawla as his city of choice, and continued to be a favorite even after Ray was captured and the court was moved there.