Ghazan was a Shiite. His brother Oljeitu, who succeeded him, started as a Christian, became a Buddhist, and ended as a Muslim; he became disillusioned by the sectarian squabbling of the various Sunni schools and turned, like his brother, to Shiism. Abu Said, his son and successor, was however a Sunni.
The Il-Khanid rulers of Iran who became converted to Islam were thus predominantly Shiite, and their Iranian subjects likewise moved gradually towards Shiism. During this time Twelver Shiism was taking on its definitive character which it has largely preserved since; a process in which Tusi played a major part. In view of Tusi's known association with Ismailism, it is difficult not to think that he must have caused Shiism to take on at least some subtle flavour of his old faith.
Whether or not this was the case, there is no doubt that Ismaili ideas continued to find expression within Islam via Sufism. As Henri Corbin, the historian of Ismailism, has said: `Ismailism...survived in Iran under the khirqa (the cloak) of Sufism, or, if one prefers, Sufism [took] on certain aspects of a crypto-Ismailism.' Nor was it only in Iran that Ismailism survived in this guise; it is possible that Ismailism influenced the development of Sufism in Spain. It may even have had an effect on mediaeval Europe. Odd echoes of Ismailism crop up in the most unlikely places.
A good example is the theme of the green bird. Sinan, it will be remembered, used to hold conversations at night with a mysterious green bird. This motif also figures in Sufism, for it was said that when a dying sheikh nominated an unexpected man as his successor, a green bird would then descend on the head of the selected individual as a sign that he was indeed the rightful spiritual heir. This is perhaps not so surprising, but what is very odd is that similar tales are told about mediaeval papal elections. It is difficult to explain this except as a roundabout transmission from Islamic, and perhaps Ismaili, sources.
Another echo of Ismailism can be found in the life of the great Sufi mystic and poet, Jalal al-Din Rumi. He had an extraordinary mystical relationship with a man called Shams-i-Tabriz, who is described as a weird figure wrapped in a a coarse felt blanket. He was more or less illiterate, but possessed of exceptional spiritual authority. He believed himself to be the mouthpiece of God - to be, in fact, divine. He was devoted to poverty, and wandered continually. So great was his influence on Rumi that the poet's followers finally had him murdered, but Rumi's most famous poetry, written subsequently, continued to be inspired by a sense of mystical identity with Shams.
According to E.G. Browne, Shams-i-Tabriz was said to have been a son of Hasan III of Alamut. This story, if true, links the spiritual legacy of the Nizaris with one of the most important mystical poets to have written in Persian - indeed, one of the foremost mystical poets in world literature.
In the nineteenth century the Ismaili Imam of the day, Hasan Ali Shah, received the title of Agha Khan from the Shah, but as a result of political difficulties he had to flee from Iran to India, where he was greeted as Imam by the Khojas.
At first his right to the title was disputed. A number of years before this, while he was still in Iran, he had sent an agent to Bombay to claim the tribute from the Khoja community which he said he was entitled to receive as their spiritual head. Some of the Khojas agreed to pay but others did not; the wrangling became bitter and in 1850 four of the recusants were openly assassinated by adherents of the Agha Khan. Four of the murderers were executed, and one of the judges at the trial, Sir Joseph Arnold, was given the task of investigating the background of the affair. The Agha Khan, who by that time was living in India, was called to give evidence in support of his claim. Finally, in 1866, Sir Joseph presented his conclusions.
His report wholly supported the Agha Khan's claims. The Khojas, Sir Joseph said, were undoubtedly members of the ancient sect of the Assassins. Four centuries earlier an Ismaili missionary had arrived in Sind from Khorasan and had made numerous converts, and from this centre the sect had spread throughout India. The missionary had followed the ancient Ismaili method of propaganda, claiming that Ismailism held the key to all religions, and he had written a book, the Desatir, which had remained the sacred book of the Khojas. Sir Joseph said that he had seen this book and that it consisted of ten chapters: the first nine dealt with nine incarnations of the god Vishnu, while the tenth dealt with the incarnation of Ali.
Ismailism, therefore, had been adapted for Indians by identifying Vishnu with Ali. For the Ismailis, all prophets and Imams, whatever their appearances, are the same; all are Divine manifestations. What could be more natural, therefore, than to represent Vishnu and Ali as simply different versions of the same Divine Impulse?
The Agha Khan, Sir Joseph concluded, was exactly what he claimed to be: the lineal descendant of Hasan II, fourth Lord of Alamut. He was, in fact, the Imam; and his descendants are so regarded by the Khojas to this day. Few spiritual leaders can boast so romantic a pedigree.