The Qarmatians (Arabic: قرامطة Qarāmita; also transliterated Carmathians, Qarmathians, Karmathians) were a syncretic religious group that combined elements of Zoroastrianism with the Ismaili Shia Islam centered in al-Hasa (Eastern Arabia), where they established a religious utopian republic in 899 CE. They are most famed for their revolt against the Abbasid Caliphate. Mecca was sacked by the sect’s leader, Abu Tahir al-Jannabi, outraging the Muslim world, particularly with their theft of the Black Stone and desecration of the Zamzam Well with corpses during the Hajj season of 930 CE.
The origin of the name "Qarmatian" is uncertain. According to some sources, the name derives from the surname of the sect's founder, Hamdan Qarmat. The name qarmat probably comes from Aramaic, and means either "short-legged," "red-eyed," or "secret teacher". Other sources, however, say that the name comes from the Arabic verb قرمط (qarmat), which means "to make the lines close together in writing" or "to walk with short steps." The word "Qarmatian" can also refer to a type of Arabic script.
The Qarāmiṭah in southern Iraq were also known as "the Greengrocers" (al-Baqliyyah) because of a preacher Abu Hatim who in 906/7 forbade animal slaughter as well as the eating of vegetables such as alliums. It is not clear if his teachings persisted.
Under the Abbasid Caliphate (750–1258 CE), various Shi'i groups organised in secret opposition to their rule. Among them were the supporters of the proto-Ismā‘īlī community, of whom the most prominent group were called the Mubārakiyyah.