The Ja'faris.

The Twelvers follow the teachings of Imam Ja'far al-Sadeq (the trustworthy), the great-grandson of Hussein. Ja'far was born about 699-700 or 702-703 in Medina and died there in 765 (allegedly poisoned). His mother, Umm-Farwa, was a great-granddaughter of Abu-Bakr (the 1st caliph). His father was Imam Muhammad-Baqer.

Ja'far was recognised as the last reigning Imam before Muhammad al-Muntazar (al-Mahdi) by the Twelvers and Isma'ili Shi'ites. He lived quietly as an authority in hadith and fiqh. He is cited with respect in Sunni 'isnads (chain of authorities, an essential part of the transmission of a tradition, with little need of this realised in early Islam). He inherited his father's following in 733 or 737. His tomb in Medina became a holy shrine and a pilgrimage spot for the Shi'ites; but this was destroyed by the Wahhabis.

The Isma'ilis follow the line to Ja'far's eldest son - Isma'il- by an Alid wife called Fatima who was the granddaughter of Hassan, and Isma'il's eldest son Muhammad. But, where the Twelvers were concerned, Isma'il died before his father, a fact which troubled the faith of some followers. Many believed Isma'il was not dead but concealed. Those who passed on to Muhammad ibn Isma'il formed the nucleus of the Isma'iliya.

The Ismailis developed a unique religious system and for a time established a powerful Fatimid caliphate, mainly in Egypt. Now the mainstream Isma'ilis are led by the Agha Khan. There are Isma'ili communities in Syria and some other Arab countries. They are also represented by the modern Khojas and Bohras - prosperous merchant communities in India and East Africa. From them split the Druze of Syria, Lebanon and Israel.

Many Ja'faris became influential during the reign of some Abbasid caliphs in Iraq and Iran. At the start of the 16th century, with the help of Turkomans, they built the Safawid Empire across Iran which stretched to parts of Afghanistan, Iraq, southern Turkey and Central Asia.

The Shi'ites include the Zaidi sect, which is ruling in the north of Yemen and has a community in the south-west of Saudi Arabia bordering Yemen. The Zaidis' principles were worked out in the 9th century. Sword in hand, they demand that their ruler must be whichever descendant of Hassan or Hussain proves to be qualified, at a given time, by his knowledge and his practical ability, though otherwise they differ little from the Sunnis. They are as moderate as the Sunnis of the Shafe'i group. In Yemen, for example, the Zaidis of the north and the Shafe'is of the south can pray in the same mosque. Historically, the Zaidis have set up small states along the Caspian Sea. But Zaidi religious leaders in the north of Yemen often cause trouble - as in the case of al-Houthis in the north of Yemen today.

Among Shi'ites awaiting al-Mahdi's return are the 'Alawites, whose faith is secret and of complex origin. The 'Alawites live in north-western Syria, with a smaller community in south-western Turkey. Through one branch of the al-Assad family, they control the army and the ruling Ba'th Party in Syria. Syrian President Bashar al-Assad  is an Alawite whose father and family, from the 'Alawite mountain town of Kirdaha, converted into Sunni Islam in order to rule Syria which is predominantly Sunni.

Several sects acknowledged as holy imams the line from Muhammad ibn al-Hanafiya, a son of Ali not by Fatima. But these died out in the 9th century. Most Shi'ite sects have acknowledged one of two lines stemming from Hussein's great-grandson Ja'far al-Sadeq, as in the case of the Ja'faris and Isma'ilis. Other Shi'ites called Imamis asserted a more exalted religious role for Alid claimants. They insisted that, in power or not, a given descendant of Ali was the divinely appointed Imam, sole authority in his time on all matters of faith and law. The more speculative among them, called Ghulat (outbidding extremists), sometimes gave the imams divine honours. The more moderate came in time to claim at least that a super-natural "Mohammadan Light", embodied in the imams, gave them super-human knowledge and power; their sufferings were means of divine grace; love of the imams and of their persecuted cause became equally obligatory with belief in God's oneness and in Muhammad's mission.