The power of the Sámánids quickly reached its zenith, and about the middle of the tenth century they were confined to Khurásán and Transoxania, while in Western Persia their place was taken by the Buwayhids. Abú Shujá‘ Buwayh, a chieftain of Daylam, the mountainous province lying along the southern shores of the Caspian Sea, was one of those soldiers of fortune whom we meet with so frequently in the history of this period. His three sons, ‘Alí, Aḥmad, and Ḥasan, embarked on the same adventurous career with such energy and success, that in the course of thirteen years they not only subdued the provinces of Fárs and Khúzistán, but in 945 A.D. entered Baghdád at the head of their Daylamite troops and assumed the supreme command, receiving from the Caliph Mustakfí the honorary titles of ‘Imádu ’l-Dawla, Mu‘izzu ’l-Dawla, and Ruknu ’l-Dawla. Among the princes of this House, who reigned over Persia and ‘Iráq during the next hundred years, the most eminent was ‘Aḍudu ’l-Dawla, of whom it is said by Ibn Khallikán that none of the Buwayhids, notwithstanding their great power and authority, possessed so extensive an empire and held sway over so many kings and kingdoms as he. The chief poets of the day, including Mutanabbí, visited his court at Shíráz and celebrated his praises in magnificent odes. He also built a great hospital in Baghdád, the Bímáristán al-‘Aḍudí, which was long famous as a school of medicine. The Viziers of the Buwayhid family contributed in a quite unusual degree to its literary renown. Ibnu ’l-‘Amíd, the Vizier of Ruknu ’l-Dawla, surpassed in philology and epistolary composition all his contemporaries; hence he was called 'the second Jáḥiẓ,' and it was a common saying that "the art of letter-writing began with ‘Abdu ’l-Ḥamíd and ended with Ibnu ’l-‘Amíd."[500] His friend, the Ṣáḥib Ismá‘íl b. ‘Abbád, Vizier to Mu’ayyidu ’l-Dawla and Fakhru ’l-Dawla, was a distinguished savant, whose learning was only eclipsed by the liberality of his patronage. In the latter respect Sábúr b. Ardashír, the prime minister of Abú Naṣr Bahá’u ’l-Dawla, vied with the illustrious Ṣáḥib. He had so many encomiasts that Tha‘álibí devotes to them a whole chapter of the _Yatíma_. The Academy which he founded at Baghdád, in the Karkh quarter, and generously endowed, was a favourite haunt of literary men, and its members seem to have enjoyed pretty much the same privileges as belong to the Fellows of an Oxford or Cambridge College.[501] Like most of their countrymen, the Buwayhids were Shí‘ites in religion. We read in the Annals of Abu ’l-Maḥásin under the year 341 A.H. = 952 A.D.:-- [Sidenote: Zeal of the Buwayhids for Shí‘ite principles.]