Al-Hakim was the Caliph of Egypt from 996 AD to 1021. He was known for Caligula like insanity and an intense violent streak that alienated almost all his followers.
Al-Hakim came to power when he was only 11, at first working under a regent, Barjuwan. At 15, he had Barjuwan killed, and soon followed it by executing many other officials. A devout Shiite Muslim, al-Hakim persecuted Christians, Jews, and Sunnis throughout his life, even destroying the Church of the Holy Sepulchre, an act that would lead to the Crusades. It was said that so many Christians converted out of fear that the conversion office couldn't handle them all.
Al-Hakim also enacted a series of insane laws, both to show his piety and seemingly for no reason at all. Even though the Muslim faith allows those of other religions to drink wine, al-Hakim ordered it banned, quickly followed by beer, and anything that could be fermented. Singers, musicians, instruments, gambling, and chess were also banned. Women were forbidden from leaving the house, such that even women's footwear was banned. Since al-Hakim loathed the barking of dogs, all dogs in Cairo were killed.
When a revolt stirred in 1005, al-Hakim brutally put it down. However, one of his chief generals came upon the Caliph hacking up the body of a child who had been one of the dissenters. The general hurried home and made out his will before al-Hakim had him executed.
Al-Hakim's behavior grew more and more destructive. First, in 1017, he began supporting heretics who were preaching that al-Hakim was a god. More revolts and riots broke out in response, but this belief created the Druze religion, which still exists today. Another time, as al-Hakim and his retinue travelled the streets of Cairo, the Caliph seized a knife from a nearby butcher's shop and killed one of his men for no reason at all.
Finally, as al-Hakim was riding in the hills south of Cairo, he disappeared. Although his bloodstained clothes were found, al-Hakim's fate remains a mystery. The Druze continue to believe that al-Hakim will return at the end of the world to usher in a Golden Age.