In the 9th century AD, the Islamic holy city of Mecca was controlled by the Abbasid Caliphate, the Ottoman Empire’s body of ruling Muslim clerics. At the time, long before the advent of the Industrial Revolution, the hajj pilgrimage in which Muslims traveled from all over the world to the Hejaz, was long and treacherous, mostly done on foot or on the backs of camels. Caravans of pilgrims crossed the Arabian desert peninsula once a year to pay their respects to Allah by circling seven times around the ka’ba, the veiled house that holds the Black Stone, a meteorite that Muslims believe was a rock that fell from their paradise in the sky. By the end of the 9th century, an obscure utopian sect called the Qarmatians arose, becoming rich by robbing the pilgrims as they made their way to Mecca.
    The origins of the Qarmatian cult are not know. What is know is that they were a Sevener sect of Isma’ili Muslims. In the world of Shi’a Muslims, a cabal existed of secret sects who were opposed to rule by the Abbasid Caliphate. One such sect, called the Mubarakkiyah had an imam who named his son as successor to his position as ruler of the religious group; his son, named Isma’il ibn Jafar died before his father did, and so the imam passed the inherited title on to his other son. This created a schism in which the Mubarakkhiya, on one side called the Seveners, decided Isma’il was the Mahdi, the messiah who would appear at the end of the world; these people believed that Isma’il had not died but rather gone into hiding to await the time of Judgment Day when he would re-emerge and take all the true believers to paradise. The other group of Mubarakkhiya accepted Ismai’l as dead but still believed he was the Mahdi who would return to announce the end of all time.
    A group of Sevener Isma’ili missionaries began traveling around the Middle East and picked up a lot of converts in what is now Iraq, the western coast of Iran, in Transoxiana, and the eastern and southern coast of the Arabian peninsula. The island of Bahrain was, for a long time their stronghold and center of power until eventually they built a settlement on the Hofuf oasis around the village of Al-Hasa in what is now Saudi Arabia. These were the Qarmatians, a messianic and utopian sect who believed the pilgrimage to Mecca to be a superstitious practice that was offensive to Allah. They were a syncretistic cult that absorbed elements of Zoroastrianism into their practices and followed a strict vegetarian diet that also excluded any vegetables from the onion family. They minted their own currency, were successful at farming, held slaves, banned taxation and eventually built up their own military.
    As the Qarmatians became more powerful under their militant ruler Abu Sa’id al-Jannabi, they instigated a reign of terror that began with the sacking of Baghdad and the eventual conquest of Mecca and Medina in 930 AD. They destroyed the city of Mecca, slaughterered thousands of people during their hajj pilgrimage  and dumped their bodies into the sacred Zamzam well, poisoning the water in the desert region where moisture was a scarce and necessary commodity. They demolished the ka’ba and stole the Black Stone which hajjis kiss as part of their rites. They carried the Black Stone back to their fortress in Al-Hasa and held it for ransom for more than twenty years.
     Thinking of the hajj as a heretical practice, the Qarmatians set up posts along the route to Mecca and terrorized, pillaged and robbed the caravans as they made their way to the Hejaz for almost a hundred years. Eventually, the Abbasid Caliphate payed a huge sum of money to the Qarmatians  in exchange for the Black Stone which had gotten cracked and broken during the raid.
    Eventually, the Qarmatians settled down but continued to grow richer by charging taxes from hajj pilgrims and exacting tributes from the Abbasids and other tribes in the surrounding areas. For a long time, they were the dominant Muslim power of the Middle East. Then in 976, the Abbasids built up an army of Iraqi and Egyptian soldiers to seize the city of Al-Hasa; the  Qarmatians held their ground for several months but the war of attrition finally wore them down and they submitted to Ottoman rule.
    The Qarmatians lasted as a rather insular secting  less and less with other Muslims over the course of several years. Finally, they were overcome by the Uyunid tribe and absorbed into their shaikhdom. Weakened and lacking in military prowess, they eventually got absorbed into the mainstream Shi’a communities.