Greek philosophers, Syriac Christians, and Nestorians fleeing persecution by the Byzantines were received by Khosro-I (78; r.531-579) of the Sassanian Empire (224-651) and commissioned to translate Greek and Syriac texts into Pahlavi. In addition to major cities like Alexandria, Constantinople and Jerusalem, people also carried ideas from Edessa (Asian Turkey), through Nisibis (Syria) and Mosul (Iraq) to Gundishapur (Iran) and Merv (Turkmenistan).
Within a century of the death of Muhammad (62; fl.610-632), the Near East countries, northwest India, the North African Seaboard and Spain were incorporated into Islam. The Arabs assimilated the knowledge of the peoples they ruled and encouraged learning of all kinds. Schools, colleges, libraries and observatories were built throughout the Arab State (632-1258). Scholars were invited to Damascus and Baghdad, and Greek manuscripts were acquired and translated.
Abu Jaffar Abdallah al-Mansur (61; r.754-775), the second caliph of the Abbasid Dynasty (750-1258), had many Syriac, Persian, Greek and Hindu documents translated into Arabic during his reign. Many more Greek manuscripts were translated by the order of the fifth caliph, Harun al-Rashid (46; r.786-809), and the dissemination of knowledge was further facilitated by the use of paper which was introduced from China around 750.
Arabic astronomy books that tabulated parameters used for astronomy calculations were known as zijes, i.e. zijat, the plural of zij and after a Persia word meaning ‘cord’. The term refers to the arrangement of threads in weaving, which the rows and columns in the tabulated data vaguely resembles.
First contact with Indian mathematics and astronomy was made in 773 when a man from Sind, a region of northwest India conquered by Islamic Arabs in 711, came to the court of al-Mansur in Baghdad carrying a work called Sindhind (‘perfection’) concerning the motions of the planets. Muhammad ibn Ibrahim al-Fazari (d.796/806) helped to translate this Sanskrit document into Arabic and the Zij al-Sindhind al-kabir (770s) was the basis of the Zij al-Sindhind of Muhammad ibn Musa al-Khwarizmi (c.780-c.850). This was revised by Maslama ibn Ahmad al-Majriti (c.950-c.1007) and translated into Latin by Adelard of Bath (c.1080-1152) in 1126.
It was soon realised, however, that the most scientifically advanced aspects of astronomy were to be found in the works of Ptolemy. The superiority of the Ptolemaic system was readily accepted and significant contributions were made to it.
Abu Abdallah Mohammad ibn Jabir al-Battani (Albategnius; c.858-929) refined the values of the precession of the equinoxes, the obliquity of the ecliptic, the length of the tropical year and found that over the course of one year the Earth-Sun distance varies. Probably independently of the Aryabhata, he introduced the use of sines and tangents in calculation, forming the basis of modern trigonometry. His most famous book Kitab al-Zij includes a set of astronomy treatises, tables and a catalogue of 479 stars. This book was translated into Latin in 1116 as De motu stellarum (‘On the motion of the Stars’) by Plato Tiburtinus.
Abd al-Rhahmab al-Sufi (Azophi; 903-86) worked on astronomical studies based on Greek works, especially the Al-magest. He made several corrections to Ptolemy’s star list and did his own brightness/magnitude estimates which frequently deviated from Ptolemy’s. He was the first to attempt to relate the Greek with the Arabic star names and constellations. In c.964 he published his Book of Fixed Stars in which he includes a ‘Little Cloud’ – actually the Andromeda Galaxy M31.
Abd al-Rahman ibn Yunus (c.950-1007) composed a major astronomy handbook called the Hakimi Zij which he prefaced with a series of more than one hundred observations, mostly of eclipses and planetary conjunctions. His time keeping tables were still in use in Cairo in the nineteenth century. Abu Ishaq Ibrahim Ibn Yahya Al-Zarqali (Arzachel; 1029-87) carried out a series of astronomy observations at Toledo and compiled them into the Toledan Tables (c.1087), which in the twelfth century were translated into Latin.
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