Follow-up question: Why did they stop accepting new members?
Firstly we need to explain who the Druze are, what they believe and a little about why this may have held weight in the Fatimid Caliphate during the 11th Century.
The Druze are a group that split off from the Shia Ismaili Muslims during the reign and after the “disappearance” of the 16th Ismaili Imam and 6th Fatimid Caliph al-Hakim bi-Amr Allah. Most often depicted as believing that al-Hakim was God incarnate the Druze’s true beliefs are not shared outside of their ethno-religious group and rarely shared within it. We can say for certain that al-Hakim is viewed as particularly special, even beyond how he is viewed by Ismailis, but we cannot say with complete certainty what the Druze actually believe.
The Ismailis were the dominant Shia group in North Africa and the Hejaz at the time, holding political power in the form the Fatimid Caliphate. They believed that their leader, the Imam, held all the authority of Muhammad other than that he would not receive revelation. As a matter of religious doctrine, the Imam was infallible. Any path he chose was the correct one.
This belief in the led to a variety of primarily Sunni Muslim polemicists accusing the Ismailis of ghulat (exaggeration) in that they ascribed attributes of prophets, or even God to the Imam. The idea that the Imam might be God, although fiercely opposed by previous Fatimid Caliphs began to spread among the populations of Egypt and Syria. Al-Hakim for his part did not oppose this spreading belief as fervently as his predecessors.
Al-Hakim’s Caliphate is perhaps the most intriguing period of the Fatimid rule. Characterised by the repression of religious minorities, women, and a huge amount of political intrigue at court. Contrasted with the Caliph building and furnishing public libraries from his personal wealth, abolishing many of the taxes that his forefathers had levied and the Caliph himself attending the religious ceremonies of the very same religious minorities seemingly in earnest.
It then may be surprising then to hear of al-Hakims massive popularity with the public of Cairo during his reign. He would frequently walk the streets without guards, laugh and joke with the citizenry and hold impromptu sessions were he would answer their questions. That’s not to say everyone loved him, he was held in contempt by many of the Christian denominations following the destruction of Churches and his forcing them to wear a certain identifying garb. Similar rulings were faced by the Jewish population. However, a lot of his repressions of these minorities were widely popular with the Sunni majority in Egypt. Being seen as a return to the days of Umar’s Caliphate.
We can get a sense of the general feeling towards, and confusion about al-Hakim as a ruler, especially around 1017 CE from the writings of Ahmad bin Ibrahim al-Naysaburi in his “Proof of the Imamate” (Ithbat al-imama). Where the author confesses the al-Hakim was like no other Muslim ruler before him. As he was the Infallible Imam he should not and could not be judged by the standard of human beings. This can lead to confusion about or rejection of his authority, his will and commands should be compared to acts of God. Al-Naysaburi then goes on to caution viewing al-Hakim as divine himself, insisting not to fall into exaggeration.
With that bit of context out of the way we can talk about the Druze themselves. The start of the Druze movement is difficult if not impossible to pin down due to relatively little information, a lot of the available sources being clearly hostile to the Druze and conflicting information with regards to pretty much everything. Arab chroniclers seemed to be largely uninterested in the Druze beyond their supposed worshiping of al-Hakim until after the Caliphs disappearance. They then write of their attempted revolution in Syria in 1032 CE and a supposed attempt by a Druze to destroy the black stone in Mecca.
One of the most important sources we have when it comes to the early Druze is Hamid al-Din al-Kirmani who wrote a treatise in November 1017 refuting al-Hasan bin Haydara al-Farghani al-Akhram’s Druze doctrines. In which he accuses the Druze of heresy: “Were it not that the Commander of the Believes (al-Hakim) has lowered a curtain of protection over both believer and hypocrite, Muslim and heretic… the response to [your doctrines] would comprise a severe punishment for you, the severing of your aorta and the application of the sword against you. But that is up to God and His guardian (al-Hakim).”
Three men who were heavily involved in the early Druze movement were the previously mentioned al-Akhram, Abu Abdallah al-Bukhari al-Durazi and Hamza bin Ali bin Ahmad al-Labbad al-Zuzani who can be viewed as a Druze prophet and Imam. Al-Durazi was despised by al-Zuzani so it is notable that the name Druze most likely derives from al-Durazi. This is likely because of al-Durazi’s open claim of the divinity of al-Hakim which was seized upon by polemicists to paint the Druze as heretics and hypocrites. The name Druze, although now used in common parlance was used as a slur used to associate all members of the movement with al-Durazi, it’s followers preferring to be called al-Muwahhidun (the people of Monotheism).
The followers of al-Durazi and al-Zuzani would clash with each other violently with one epistle by al-Zuzani chiding al-Durazi: “…you would destroy yourselves and burn in the fire that your smoke would reach… On that day you were some 500 heavily armed men… Forty of you were killed. Those fled who fled. Were it not for the mercy of our lord (al-Hakim) none of you would have escaped.”
Al-Zuzani deliberately structured his teachings to mimic the Ismaili doctrine espoused by the Fatimid Caliphate, assigning individuals as physical embodiments of parts of Ismaili doctrine. He also quoted from the “sessions of wisdom” given by the heads of the Ismaili Dawa. The people of the Fatimid Caliphate would likely be more receptive or at least aware of its meanings and parallels as Ismaili doctrine was preached and taught by the state attempting to convert its population to Ismailism peacefully (although the first Fatimid Caliph Abdallah al-Mahdi Billah had attempted to violently convert the population under his rule). He also took advantage of a growing feeling that Ismailism was tending toward a much more legalistic and ritualistic than it had been previously. By claiming to focus on the inner dimension of faith the Druze could do away with exoteric Islamic laws and rituals. This of course led to accusations of heresy as well as the persistent claim that either al-Durazi or al-Zuzani sent one of their followers to destroy the black stone in Mecca in a near parallel to the earlier Qarmatians actions in rejecting the zahir (exoteric) of Islam.