The diversity of creeds among the various Moslem sects had also, from the beginning, imperilled the unity of the Arabian world within the Ottoman Empire by endangering its religious unity. By the side of the Sunnis, or Orthodox Moslems, the Shia—viz., the rebels or heretics, belonging to a schism which is almost as old as Islam itself—recognise nobody but Ali as the lawful successor of Mohammed. According to them, the title of Caliph should not go outside the Prophet’s family, and his spiritual powers can only be conferred upon his descendants; so, from a religious point of view, they do not recognise the power of the other dynasties of Caliphs—for instance, that of the Ottoman Sultans. As Ali, the Prophet’s son-in-law, was killed at Kufa in Mesopotamia, and as Ali’s sons, Hassan and Hossein, were also massacred at Kerbela, near the ruins of Babylon, together with some of their descendants who had a lawful right to the title of Imam, Mesopotamia is looked upon by the Shia as their Holy Places. Many wealthy Persians, to whom the worship of the members of Ali’s family has become a symbol and who consider their death as a religious sacrifice, have their own coffins carried to Mesopotamia that their bodies may lie in the holy necropolis of Kerbela or of Nejef, to the north-east of Mecca and Medina; and as a great many Arabs of Mesopotamia are still Shia, this schism practically divides the Persian world from the Turkish world. But though the Persians, who have never recognised any Caliph, and for the last thirteen hundred years have been waiting till the Khilafat should revert to the lineal descent of Ali, the Prophet’s son-in-law, to acknowledge a Caliph’s authority, do not recognise the Ottoman Caliphate, yet their monarchs do not seek to deprive the Sultan of his title of Caliph to assume it themselves. So their case is entirely different from that of the people of Morocco, who do not recognise the Ottoman Caliphate because their own sovereigns, as descendants of the Prophet, profess they have an hereditary right to hold the office of Caliph within the frontiers of their State. The Shia faith has even spread as far as India and the Sunda Isles; and so the opposition between Shia and Sunnis may play an important part in freeing Mesopotamia from the Turkish influence of Constantinople. Yet the English occupation has been so bitterly resented in Mesopotamia that the Shia Mujtahids, or imams of Nejef and Kerbela, have lately asked for the restoration of Turkish sovereignty over these towns, where are the two famous holy shrines of Islam. Moreover, the controversy on the question whether the Sultans of Turkey have a right to the Caliphate, because they do not belong to the tribe of Koreish, in which the Prophet was born, seems to have come to an end among the Moslems, or at least to have been laid aside in view of the present events.