His reign was notable for several things: the tender age - eleven - at which he succeeded his father Abū Mansūr Nizār al-ʿAzīz as Khalīfa, and the stability of the Fatimid dynasty that this successful transfer of power demonstrated; his extension of Fatimid rule to the emirate of Aleppo; his importance as a central figure in the Druze religious sect; and perhaps most importantly what many have called his "eccentricity."
As one prominent journal has noted, al-Ḥākim has attracted the interest of modern historians more than any other member of the Fatimid dynasty because of
Al-‘Azīzah is credited with birthing Sitt al-Mulk, one of the most famous women in Islamic history, who had a stormy relationship with her half-brother al-Ḥākim and may have had him murdered. Some, such as the Crusader chronicler William of Tyre, claimed that this Coptic woman was also the mother of Caliph al-Ḥākim, though most historians dismiss this. William of Tyre went so far as to claim that al-Ḥākim's destruction of the Church of the Holy Sepulchre in 400/1009 was due to his eagerness to disprove taunts that he was a Christian born of a Christian woman. By contrast, the chronicler al-Musabbihi recounts that in 371/981, al-Ḥākim's Muslim mother sought the aid of an imprisoned Islamic sage named ibn al-Washa and asked him to pray for her son who had fallen ill. The sage wrote the entire Qur'ān in the inner surface of a bowl and bid her wash her son out of it. When al-Ḥākim recovered, she demanded the release of the sage in gratitude. Her request was granted and the sage and his associates were freed from prison.
Druze sources claim that al-Ḥākim's mother was the daughter of ‘Abdu l-Lāh, one of al-Mu‘īzz li Dīn al-Lāh's sons and therefore al-‘Azīz's niece. Historians such as Delia Cortese are critical of this claim:
Because it had been unclear whether he would inherit his father's position, this successful transfer of power was a demonstration of the stability of the Fatimid dynasty.
Besides his son, al-Ḥākim had a daughter named Sitt Misr (d. 455/1063) who was said to be a generous patroness and of noble and good character.
Al-Ḥākim's most rigorous and consistent opponent was the Abbāsid Caliphate in Baghdad, which sought to halt the influence of Ismailism. This competition led to the Baghdad Manifesto of 1011, in which the Abbāsids claimed that the line al-Ḥākim represented did not legitimately descend from ‘Alī.
Al-Ḥākim also struggled with the Qarmatiyya rulers of Bahrain, an island in the Persian Gulf as well as territory in Eastern Arabia. His diplomatic and missionary vehicle was the Ismā'īlī da‘wah "Mission", with its organizational power center in Cairo.
Al-Ḥākim's reign was characterized by a general unrest. The Fatimid army was troubled by a rivalry between two opposing factions, the Turks and the Berbers. Tension grew between the Caliph and his viziers (called wasītas), and near the end of his reign the Druze movement, a religious sect centered around al-Ḥākim, began to form. It was the Druze who first referred to al-Ḥākim as "Ruler by God's Command" and members of that sect are reported to address prayers to al-Ḥākim, whom they regard as "a manifestation of God in His unity.
In 1004, al-Ḥākim founded the Dār al-Ḥikmah "House of Knowledge", with its great public library; there philosophy and astronomy were taught in addition to purely Islamic studies of the Qurʾān and ahādīth. In 1013 he completed the mosque in Cairo begun by his father, the Masjid al-Ḥākim "Ḥākim's Mosque" whose official name is "Jami‘-u l-Anwar". The mosque fell to ruins and was restored to its former glory some twenty years ago by Dr. Syedna Mohammed Burhanuddin after much research and expense.
In 1005, al-Ḥākim ordered a public posting of curses against the first three Caliphs (Abū Bakr, ‘Umār and ‘Uthmān ibn ‘Affān) and against ‘Ā'isha (wife of Muhammad) all for opposing the claim of Muhammad's cousin and son-in-law ‘Alī, who had demanded the position of Caliph for himself and his descendants. The founder of the Umayyad caliphate, Mu‘awiyah I, and others among the Ṣaḥābah of Muhammad were also cursed. After only two years of posting the curses, al-Ḥākim ended the practice. During this era, al-Ḥākim ordered that the inclusion of the phrase as-salāh khayr min an-nawm "prayer is preferable to sleep", which followed the morning prayer be stopped - he saw it as a Sunni addition. In its place he ordered that ḥayyi ‘alā khayr al-‘amal "come to the best of deeds" should be said after the summons was made. He further forbade the use of two prayers - Salāt at-Tarāwih and Salāt ad-Duha as they were believed to have been formulated by Sunni sages.
In 1005, following the tradition of the caliphate, al-Ḥākim ordered that Jews and Christians follow ghiyār "the law of differentiation" - in this case, the mintaq or zunnar "belt" (Greek ζοναριον) and ‘imāmah "turban", both in black. In addition, Jews must wear a wooden calf necklace and Christians an iron cross. In the public baths, Jews must replace the calf with a bell. In addition, women of the Ahl al-Kitab had to wear two different coloured shoes, one red and one black. These remained in place until 1014.
Al-Ḥākim engaged in other erratic behaviour in 1005: he ordered the killing of all the dogs in Egypt and had them discarded in the desert. He also forced the inhabitants of Cairo to work at night and go to bed in the mornings and severely punished anyone caught violating his orders.
Following contemporary Shiite thinking, during this period al-Ḥākim also issued many other rigid restrictive ordinances (sijillat). These sijill included outlawing entrance to a public bath with uncovered loins, forbidding women from appearing in public with their faces uncovered, and closing many clubs and places of entertainment.
While it is clear that Hamza ibn Ahmad was the Caliph's chief dāʿī, there are claims that al-Ḥākim believed in his own divinity.
Other scholars disagree with this assertion of direct divinity, particularly the Druze themselves, noting that its proponent was ad-Darazi, who (according to some resources) al-Ḥākim executed for shirk. Letters show that ad-Darazi was trying to gain control of the Muwahhidun movement and this claim was an attempt to gain support from the Caliph, who instead found it heretical.
The Druze find this assertion offensive; they hold ad-Darazi as the first apostate of the sect and their beliefs regarding al-Ḥākim are complex. Following a typical Isma'ili pattern, they place a preeminent teacher at the innermost circle of divinely inspired persons. For the Druze, the exoteric is taught by the Prophet, the esoteric by his secret assistants, and the esoteric of the esoteric by Imām al-Ḥākim.
Confusion and slander by opponents of the Druze were generally left uncorrected as the teachings of the sect are secret and the Druze preferred taqiyya when independence was impossible.
According to ibn Najjar in History of Baghdad, al-Ḥākim conspired to draw the attention of the Muslim world towards Egypt by planning to steal the bodies of Muhammad and his companions Abū Bakr and ‘Umar. Al-Ḥākim built an expensive enclosure to hold their remains and sent Abū l-Fatuh to Madina to carry out the plan. When Abū al-Fatuh arrived in Madina, the residents learned of this plot and gathered around him threateningly. Qari Zalbani recited the following verses of the Qur’an to him:The residents of Madina became furious and were about to kill Abu al-Fatuh and his soldiers, when he became afraid and said, "I shall never carry out this dirty plan even if the ruler kills me." In the meanwhile, a big storm swept through the area, destroying many houses and killing many animals and people. Abū al-Fatuh fled from Madina and nothing more came of al-Ḥākim's plot.
In 1014, he ordered women not to go out at all, and ordered the shoemakers not to make any women's shoes. However Said Gafurov considers information about all these measures unreliable because they have same origin of Fatimides opponents and Hakim inheritors, and tries finds rational explanation for these measures. For example, forbade of women shoes production is considered related to necessity of lack of leather mobilisation reserves, necessary for the Fatimid Army before a Large War.
Al-Ḥākim killed many of his officials both high and low in rank: his tutor Abū l-Qasim Sa‘īd ibn Sa‘īd al-Fāriqī, most of his viziers, judges, poets, physicians, bathhouse keepers, cooks, cousin, soldiers, Jews, Christians, intelligence gatherers and even cut the hands of female slaves in his palace. In some cases, he did the killing himself.
In 1009, he destroyed the Church of the Holy Sepulchre in Jerusalem, then under Fatimid control. The church was later rebuilt by his successor with help from the Byzantine Empire. Said Gafurov denies this fact pointing out that all our sources about it are sharply Anti-Hakimite. In his version the keys of Church of the Holy Sepulchre were simply taken from the Roman Catholics and given to monophysite or Nestorian christians.
Although Christians were not allowed to buy slaves, male or female, and had few other privileges, they were allowed to ride horses on the condition that they ride with wooden saddles and unornamented girths.
Towards the end of his reign he became increasingly erratic and feared by his officials, soldiers and subjects alike. Muslim and Christian dignitaries alike went to his palace kissing the ground, and stood at the palace gates asking him for forgiveness, and not to listen to any rumors that were spreading. They raised a petition to al-Ḥākim and he forgave them.
Al-Ḥākim was succeeded by his young son ‘Alī az-Zāhir under the regency of his sister, Sitt al-Mulk.