The Shi`ite canon law is dealt with separately, but some mention of two outstanding sects is here in place. The Ibadites (see MAHOMMEDAN RELIGION: _Sects_) have a system of canon law which in essentials is of older codification than that of any of the orthodox schools, going back to Abdallah ibn Ibad himself, of the first century of the Hijra (Hejira). Its basis is above all the Koran, then a sparing use of traditions, natural to their early origin, and finally the agreement of their own learned men, again natural to an extreme dissenting sect, and it still rules the Ibadite communities at Oman, Zanzibar and the Mzab in southern Algeria. At all these places they, the last descendants of the Kharijites, hold severely apart, while the other Moslems shrink from them as heretics of the worst. Not nearly so far from ordinary Islam, but still of an extreme self-conscious Puritanism are the Wahhabis. They are really Hanbalites, but apply the rules of that school with uncompromising, reforming energy. The doctrine of the agreement of the Church of Islam they reject; only that of the immediate companions of Mahomet is valid. The people of Mahomet can err and has erred; each man must, on his own responsibility, draw his doctrine from the Koran and the traditions. Here they follow the Zahirites. All these schools of law administer a scheme of duties, which, as has already been remarked, comes nearest to the canon law of the Roman Church, and which for centuries has had only a partial connexion with the real legal systems of the Moslem peoples. Among the Wahhabis and Ibadites alone is it the whole of law. Elsewhere, since the Omayyad period, its courts have been in great part pushed aside by others, and its scheme has come to be regarded as an expression of impossible theory, to be realized at best with the coming of the millennium. The causes and methods of this change call now for detailed notice.