In what follows...

In what follows, an attempt will be made to trace the course of intellectual revolution which Muslim thought brought about in Persia, Turkey, China, India, and Indonesia. Persia Islam was introduced to the land of Persia in 7/628 by the himself, when through an epistle addressed to Khusrau Parviz, the then Persian monarch, he extended an invitation to him and his subjects to embrace Islam: to affirm the unity of God and the apostleship of Muhammad, to do good and to refrain from evil.

In olden times no king, much less a Persian potentate, would receive a direct communication from an unknown person without getting flared up, the act being regarded as an instance of insolence and sacrilege. Accordingly, the Prophet's letter was torn to pieces and his emissary expelled with ignominy and disgrace. On hearing this, the Prophet felt sad and prophesied an early downfall of Khusrau's Empire.

It was during the rule of the first Caliph that, as a response to this insult, the Muslim forces, under the leadership of General Sa'd, invaded Persia and inflicted a terrible defeat on the Persian army in the battle of Qadisiyyah. This battle served as a prelude to a series of defeats which the Persians suffered at the hands of the Arabs and which sealed their fate in a short period of ten years after the delivery of the Prophet's letter.

King Yazdigird, a lad of eighteen, was probably the last ruler to make a futile attempt against the Muslims. His Chinese and Turkish mercenaries deserted him on the first onslaught of the Arabs, while he was himself plundered and assassinated by a villager in whose hut he had taken refuge after fleeing from the battlefield. In the first/seventh century the Persian Empire like the Byzantine Empire was tottering under the crushing weight of despotism.

Persecutions born of reli­gious dissensions were the order of the day. Zoroastrianism was the State religion and its priests, not content with the spiritual authority they enjoyed by virtue of their office, also held positions of trust and responsibility in the administration of the State. A campaign of vilification followed by persecutions started against the adherents of the older forms of religion in Persia, among which ranked Jews, Christians, Buddhists, Sabaeans, Gnostics, and Manichaeans.

All the older faiths and creeds longed to breathe freely and freshly in an atmosphere of toleration and comradeship which they eventually found in the teachings of Islam.