Wahhabism: a short guide
Extremist groups like Islamic State are thought to adhere to an extreme version of Wahhabism, the strain of Islam that developed in Saudi in the 18th century
In July 2013, Wahhabism was identified by the European Parliament in Strasbourg as the main source of global terrorism.
This brand of Islam has become increasingly influential, partly because of Saudi Arabian money and partly because of Saudi Arabia's central influence as protector of Mecca - the location for the annual hajj pilgrimage that's central to the practice of Islam.
The official position is that the Grand Mufti of Saudi Arabia has condemned Isil, insisting "the ideas of extremism, radicalism and terrorism do not belong to Islam in any way".
Somewhat paradoxically, however, members of the Saudi ruling class have applauded Wahhabism for its Salafi piety - ie its adherence to the original practices of Islam - and the movement's vehement opposition to the Shia branch of Islam.
In the 1970s, with the help of funding from petroleum exports and other factors, Saudi charities started funding Wahhabi schools and mosques across the globe. and the movement underwent explosive growth.
The US State Department has estimated that over the past four decades Riyadh has invested more than $10bn (€8.9bn) into charitable foundations in an attempt to replace mainstream Sunni Islam with the harsh intolerance of its Wahhabism. EU intelligence experts estimate that 15 to 20pc of this has been diverted to al-Qaeda and other violent jihadists.
The movement now has worldwide influence.
Founded by Mohammed Ibn Abd al-Wahhab (1703-92), it stresses the absolute sovereignty of God. Ibn Abd al-Wahhab also rejected any reliance on the intercession of Mohammed and denounced pilgrimages to saints' tombs, declaring that their domes or shrines should be destroyed.
As an opposer of innovation, he advocated a return to what he saw as the purity of the first generation of Islam, the salaf and the teaching of any school of law. His ideas were deeply influenced by the teachings of Ibn Taymiyah (1263-1328), who saw the state as an adjunct of religion and opposed discursive theology.
Ibn Taymiyah also branded the Mongols of his day as kafirs (unbelievers), even though they professed the main tenets of Islam. In this, he has been imitated by modern Islamist movements which excommunicate those who profess Islam without following it rigorously. These ideas were further developed in the 20th century by Sayyid Qutb.
Wahhabists enforce public attendance at prayers, forbid shaving and the smoking of tobacco. Their mosques are plain. By the middle of the 18th century, they dominated the Arabian peninsula with the political support of the Al Saud, the ruling royal family that remains in power.
In 1925, the Wahhabists seized Mecca, but the state has continued to allow pilgrims of all Muslim traditions to observe their rites during the hajj. Even so, the Interior Ministry funds the religious police, who seek out illegal alcohol and ensure shops are shut during mosque time.
Since the 1980s, unemployed young people have been attracted to neo-Wahhabist groups embracing salafiyah, the ideology of primitive Islam, who seek social justice as well as the imposition of Koranic punishments.
The terrorism links
The exclusivism of Ibn Taymiyah combined with the use of violence advocated by modern ultra-Wahhabists such as al-Qaeda, Isil and Boko Haram, have now given rise to cells of activists outside Saudi Arabia, ready to commit terrorist outrages.
The irony of this is that the Prophet Muhammad and Imam Ali (his cousin) seemed to warn against the rise of extremism in Kitab Al Fitan - a compilation of hadiths (Islamic tradition) relating to the end of times, put together by prominent scholar Nuyam bin Hammad in 229 AH.
In it Imam Ali recalled the Prophet saying: "If you see the black flags, then hold your ground and do not move your hands or your feet. A people will come forth who are weak and have no capability, their hearts are like blocks of iron. They are the people of the State (literally the people of Al Dawla), they do not keep a promise or a treaty. They call to the truth but they are not its people. Their names are (nicknames like Abu Mohammed) and their last names (are the names of town and cities, like Al Halabi [and now al-Baghdadi]) and their hair is loose like women's hair. (Leave them) until they fight among themselves, then Allah will bring the truth from whoever He wills."