Al-Muktafi, however, was of a sickly disposition since childhood; indeed, he may have been ill for much of his reign. In late spring 908 he fell gravely ill, and for about three months, the caliph lay incapacitated, his situation alternately improving and deteriorating. It soon became clear, however, that he would not survive his illness. Al-Muktafi had nine sons, but they were all underage, and due to his illness, he was unable to determine a successor. The vizier, al-Abbas al-Jarjara'i, sounded out the leading officials of the bureaucracy on the issue—an unprecedented act that demonstrated the monopoly of power now exercised by the civilian bureaucrats. Muhammad ibn Dawud al-Jarrah favoured the experienced and capable Abbasid prince Abdallah ibn al-Mu'tazz, but the vizier eventually followed the advice of Ali ibn al-Furat, who suggested al-Muktafi's 13-year-old brother Ja'far, on the grounds that he would be weak and pliable, and easily manipulated by the senior officials. The choice of Ja'far, who became Caliph al-Muqtadir (r. 908–932), was, in the words of historian Hugh N. Kennedy, "a sinister development" and inaugurated one "of the most disastrous reigns in the whole of Abbasid history [...] a quarter of a century in which all of the work of [al-Muqtadir's] predecessors would be undone".