(Rhazes), who was named director of the newly established al-Mu'tadidi hospital in Baghdad; and the mathematician and astronomer al-Battani. One of the leading intellectual figures of the period was al-Mu'tadid's own tutor, Ahmad ibn al-Tayyib al-Sarakhsi, a pupil of the great philosopher al-Kindi. Al-Sarakhsi became a close companion of the Caliph, who appointed him to the lucrative post of market supervisor of Baghdad, but was executed in 896, after angering the Caliph. According to one account, al-Qasim ibn Ubayd Allah—who is frequently featured as the villain in anecdotes of al-Mu'tadid's court—inserted al-Sarakhsi's name in a list of rebels to be executed; the Caliph signed the list, and learned of his mistake only after his old master had been executed. Justice and punishment under al-Mu'tadid In the dispensation of justice, he was characterized by what Malti-Douglas describes as "severity bordering on sadism". While tolerant of error and not above displays of sentimentality and tenderness, when his wrath was aroused he resorted to torture in the most ingenious ways, and had special torture chambers constructed underneath his palace. Chroniclers such as al-Mas'udi and the Mamluk historian al-Safadi describe in great detail the tortures inflicted by the Caliph on prisoners, as well as his practice of making an example of them by having them publicly displayed in Baghdad. Thus the Caliph is reported to have used bellows to inflate his prisoners, or buried them upside down in pits. At the same time they justify his severity as legitimate, being in the interests of the state. Malti-Douglas remarks that when al-Safadi compared al-Mu'tadid with the founder of the Abbasid state, calling him "al-Saffah the Second", this was not only to emphasize his restoration of the Caliphate's fortunes, but also a direct allusion to the meaning of al-Saffah's name, "the Blood-Shedder". Death and legacy Al-Mu'tadid died at the Hasani Palace on 5 April 902, at the age of either 40 or 47. There were rumours he had been poisoned, but it is more likely that the rigours of his campaigns, coupled with his dissolute life, severely weakened his health. During his final illness, he refused to follow the advice of his physicians, and even kicked one of them to death. He left behind him four sons and several daughters. Of his sons, three—al-Muktafi, al-Muqtadir, and al-Qahir—would rule as caliphs in turn and only one, Harun, did not become caliph. Al-Mu'tadid was the first Abbasid caliph