its rule, either willingly or out of fear. These peoples professed diverse religions—Judaism, Zoroastrianism, Christianity, idolatry, and others. Many of them, such as the Persians and the Romans, had once enjoyed vast dominion, which the Muslims then wrested from them. Their arrogance and pride made them loath to live under Muslim authority, all the more so because they had always regarded the Arabs as among the most insignificant of nations. The Jews in particular faced Islam and its Messenger with hostility from the very first, striving to annihilate it through every conceivable ploy and conspiracy. When all of these enemies despaired of overcoming Islam by confronting it openly with force, they turned their energies and machinations to intrigue, plotting, and the assassination of its leading figures.

Some of them outwardly embraced Islam with the deliberate intention of corrupting it and fragmenting the ranks of its people. Such a project had to be the product of careful study, reflection, and planning; moreover, there may have been coordinated groups—Zoroastrians, Jews, Christians, Hindus, and others—working together. Each faction could well have had its own institutions dedicated to undermining Muslim doctrine, convinced that the Muslims could not be defeated unless their creed was first subverted. The effects of these conspiracies therefore began to surface little by little.

Thus the rightly guided Caliph ʿUmar ibn al-Khattab was killed by a Zoroastrian hand (1), quite possibly as part of a joint Magian-Jewish plot. After him, the Caliph ʿUthmān was slain (2) by suspicious rabble, incited by some of the shrewd schemers among the Jews and the Zoroastrians (3).

Soon afterward, the doctrine that denies the divine decree—qadar—appeared. The first to introduce it in Iraq was a man from Basra named Siswayh, a descendant of the Zoroastrians, and it was from him that Maʿbad al-Juhani (4) took the idea.