This extreme attachment to the Imams is probably due to two things. In the first place, there can be no doubt that the cause of Ali and his sons was taken up in Persia as an outlet to national jealousy, for the Aryan converts were not sorry when a pretext occurred for differentiating themselves from the majority of their Arab conquerors. In the Shiah religion the early Khalifs, who ruled Islam while the holy Imams were still alive, are held up to the bitterest execration, and Omar in particular, who, by the way, was the conqueror of Persia, takes much the same place in the Shiah system that Judas Iscariot does in the Christian. [Illustration: SMALL SQUARE IN YEZD. To the left is a small Nakhl, and in the centre a mosque door with the inscription “Ya Ali.”] Secondly, the influence of sects of mystics, professedly Mohammedan but having in their doctrines a distinctly pantheistic tendency, must be remembered. Ancient Persia was full of pantheism, and when it became Mussulman the inclination towards such teaching still continued, for the broader views held by the Shiahs as to freedom of interpretation in reading the _Quran_ gave a possible status in the country to very heretical sects. These Persian mystics often preferred to make the Imams, especially Ali, at least as prominent in their systems as Mohammed, whose teaching was more difficult to bend to their purposes; and although the ordinary Yezdi is certainly not a pantheist, they have undoubtedly intensified his enthusiasm for the personalities of the Imams, and through their poetry they have familiarised him with religious expressions of a somewhat unorthodox character. This is in some ways an advantage to the missionary, but he must beware that it does not give him a false view of the progress that he is making. As to the theory of the divinely appointed Imamate it might be urged that the retention of the whole glory of the early sainthood for the close relations and descendants of the prophet is an excess of zeal that Mohammed would have greatly approved. However this may be, the doctrine is not obviously opposed to Mohammedanism.