The real impetus came ultimately from transmitted Hellenism, but this influence was derived immediately from the Nestorians in philosophy proper, and from the Nestorians and the Zoroastrian school at Junde-Shapur in medicine. A good deal later comes the influence of the pagan school at Harran, which also had a neo-Platonic tendency. When the second Abbasid Khalif al-Mansur passed by Harran on his way to fight against the Byzantine Emperor he was astonished to observe the strange appearance of some of the citizens who came out to meet him, wearing their hair long and having close fitting tunics. When the Khalif asked whether they were Christians, Jews, or Zoroastrians, they replied that they were neither. He then enquired if they were “people of a book,” for it was only those who possessed written scriptures who could be tolerated in Muslim dominions; but to this they returned such hesitating and ambiguous replies that the Khalif at length felt convinced that he had discovered a colony of pagans, as was the case, and he ordered them to adopt some one or other of the “religions of the book” before his return from the war, or to suffer the penalty of death. At this they were greatly alarmed: some of them became Muslims, others Christians or Zoroastrians, but some declined to desert their traditional beliefs. These latter naturally had the most anxious time, wondering how they could contrive to evade the Khalif’s demands. At length a Muslim lawyer offered to show them a way out of the difficulty if they paid him a substantial fee for doing so. The fee was paid and he advised them to claim to be Sabians, because Sabians are mentioned in the Qur´an as belonging to a religion “of the book,” but no one knew who the Sabians were. There is a sect known as _Sabiyun_ or _Sabaean_, whose religion is a strange mixture of ancient Babylonian state worship, Christian Gnosticism, and Zoroastrianism, living in the mashe lands near Basra, but they had always been careful to keep their religious beliefs secret from all outsiders, and although they were no doubt the sect mentioned in the Qur´an under the name of _Sabiyun_ or _Sabians_, none could prove that the pagans of Harran were not also comprised under this term. The Khalif never did pass back by Harran, the pagans who had assumed the name of Sabian continued to use it, those who had become Christians or Zoroastrians reverted to their old faith and submitted to its new name; those who had become Muslims were obliged to remain so as the penalty of death lay upon any who became renegades from that religion.