followed by Umm Musa, a descendant of one of the Abbasid clan's junior branches. Her plotting for her favourites, the corruption of her family, and her hostility towards the "good vizier" Ali ibn Isa al-Jarrah, who was dismissed due to her machinations in 917, are underlined in the chronicles of the period. However, when she married her niece to Abu'l-Abbas, a grandson of al-Mutawakkil (r. 847–861), her rivals were quick to accuse her of aspiring to overthrow the Caliph and place her nephew on the throne. In 922/3, she was arrested and replaced by Thumal, who tortured Umm Musa, her brother, and her sister, until they had revealed where her treasure—reportedly valued at one million gold dinars—was hidden. Thumal enjoyed a reputation for cruelty; her first master, Abu Dulaf, had used her to punish servants who displeased him. Another qahramāna, Zaydan, was the antithesis of Thumal: her house was used to jail several senior officials after they were dismissed, but it was a comfortable captivity, and she often provided refuge to those persecuted by their political rivals. Policies and events The stand that had been made during the last four reigns to stay the decline of the Abbasid power at last came to an end. From al-Muqtadir's reign on, the Abbasids would decline. Yet, at the same time, many names that would become famous in the world of literature and science lived during this and the following reigns. Among the best known are: Ishaq ibn Hunayn (d. 911) (son of Hunayn ibn Ishaq), a physician and translator of Greek philosophical works into Arabic; ibn Fadlan, explorer; al Battani (d. 923), astronomer; al-Tabari (d. 923), historian and theologian; al-Razi (d. 930), a philosopher who made fundamental and lasting contributions to the fields of medicine and chemistry; al-Farabi (d. 950), chemist and philosopher; Abu Nasr Mansur (d. 1036), mathematician; Alhazen (d. 1040), mathematician; al-Biruni (d. 1048), mathematician, astronomer, physicist; Omar Khayyám (d. 1123), poet, mathematician, and astronomer; and Mansur al-Hallaj, a mystic, writer and teacher of Sufism most famous for his self-proclaimed attainment of unity with God (which was misunderstood and disputed as divinity), his poetry, and for his execution for heresy by al-Muqtadir. By the time of al-Muqtadir's reign, there had been war for some years between the Muslims and the Greeks in Asia, with heavy losses for the most part on the side of the Muslims, many of whom were