of his enemies for a whole day, before a 'miraculous' appearance of al-Hakim forced their attackers to withdraw. Hamza places this miracle on the day of the Islamic new year (1 Muharram 410 AH/9 May 1019 CE), which thus marked the resumption of the Druze's missionary activity (the "divine call"). The riots spread, the discipline of the soldiers collapsed, and order was restored only after much of Cairo had been burned down. Chroniclers hostile to al-Hakim, like Yahya of Antioch or later Sunni historians, saw in this a deliberate attempt by the Caliph to punish the Cairenes for opposing the Druze teachings. Final years The doctrines current during the later years of al-Hakim's reign were apparently propagated simultaneously and independently by a number of missionaries. Their roles and their mutual relationships are unclear. Al-Akhram for example is assigned a major role by later Sunni historians, but is passed over in silence by Hamza. Nevertheless, Hamza does appear to have played a leading role: even if al-Darzi had his own followers, the sources do suggest that he acknowledged Hamza's leadership on some matters. In any event, with the death of al-Darzi, by 1019 Hamza was the almost undisputed leader of the new movement. More importantly, it was Hamza who built up the new religion into an organized movement similar to the official Isma'ili , by appointing his own in Egypt and Syria. He furthermore selected some of his senior disciples and established them in a hierarchy of "ranks", headed by himself (see below). Al-Hakim's disappearance and Hamza's death On the night of 13 February 1021, Caliph al-Hakim disappeared during one of his usual nightly rides, likely the victim of a palace conspiracy. Power was seized by his sister, Sitt al-Mulk, as regent for al-Hakim's son, al-Zahir (). The new regime quickly reversed many of al-Hakim's controversial policies, instituting a return to Isma'ili orthodoxy. As part of this Isma'ili reaction, the Fatimid authorities launched a severe persecution against the Druze movement, with the result that the seven Islamic years that followed (411–418 AH) are a period of silence in the Druze sources. A few months after al-Hakim's disappearance, Hamza wrote a farewell epistle (, 'Epistle of Occultation'), in which he announced his retirement and al-Hakim's concealment or occultation (). In it, Hamza urged his followers to keep the faith, as the period of trials would soon pass, and the end times would