In 751 in Samarqand the secret of paper making was taken from some Chinese prisoners and in 795 a paper factory was established in Baghdad.
Idries Shah mentions that one of Haroun al Rashid’s companions were the Barmenicides, earlier, keepers of the Buddhist shrines in Afghanistan, and he says the Sufi tradition as it developed and moved to other centres like Moorish Spain, kept drawing on this legacy.
In the 8th and 9th century, the entire scientific and philosophical legacy of the world was being rendered into Arabic : medicine, natural sciences, astronomy, ethics, metaphysics, philosophy, alchemy and magical texts were being studied in a bureau of translations under the Abbasid Caliphs of Baghdad.
The caliph Mamun was responsible for the translation of Greek works into Arabic. He founded in Baghdad the Academy of Wisdom, which took over from the Persian university of Jundaisapur and soon became an active scientific center. The Academy's large library was enriched by the translations that had been undertaken. He entered into relations with the emperors of Byzantium, gave them rich gifts, and asked them to give him books of philosophy which they had in their possession. These emperors sent him those works of Plato, Aristotle, Hippocrates, Galen, Euclid, and Ptolemy which they had. Scholars of all races and religions were invited to work there. They were concerned with preserving a universal heritage, which was not specifically Islamic and was Arabic only in language. The sovereign had the best qualified specialists of the time come to the capital from all parts of his empire.The Encyclopaedia of Islam also mentions the influence of two Indian sources: the Brahmasphuta Siddhanta of Brahmgupta (628) which was brought to the court at Baghdad in 771 and was used as a model in Arabic by Ibrahim b Habib al Fazari and Yaqub b Tariq; and the treatise of Aryabhatta, composed in 500, from which Abul- Hasan al Ahwazi derived his tables of planetary movements.As Joseph Campbell puts it: “the light of Hellenistic learning had been quenched for Europe when, in the year 529, the Byzantine Emperor Justinian ordered the schools of pagan philosophy closed in Athens. The only remaining repositories of Greek philosophy and science then were Sassanian Persia, Gupta India and Ireland, the one flickering candle in the West…(till) Baghdad became within a few decades the most important seat of classical learning in the world”