The Abbasid Caliphate

The Abbasid Caliphate has only been mentioned so far as a target of the Assassins, but deserves more attention. Descended from Muhammad's uncle Abbas, the caliphate took power from the Umayyad caliphate and ruled from 750 until its conquest by Mongols in 1258.

That means that the Abbasid Caliphate was "in charge" during many of the Islamic interaction with Europe mentioned in this blog:

• Abu Ma'shar, the Father of Arab Astrology, who brought commentaries on Aristotle to Western Europeans
• The astronomer Abd al-Rahman al-Sufi, who reconciled Greek and Arab star charts
• Averroes the Commentator
• Avicenna the surgeon
• ...and, of course, it was during this time that Algebra came to be

Besides math and philosophy, the Abbasid Caliphate was at the forefront of technology, adopting the use of Chinese paper-making techniques and gunpowder. Arabs developed the sextant, windmills for industrial use, and kerosene from petroleum.

The Abbasid's first capital was Kufa, on the banks of the Euphrates, but they shortly chose a different city, whose only shortcoming was that it did not exist.

On 30 July, 762, that would change; but that's a story for tomorrow.

Father of Arab Astrology

Abu Ma'shar, from his Introduction to Astronomy

Albertus Magnus, Robert Grosseteste, Geoffrey Chaucer—well-known names from the Middle Ages denoting a Dominican scientist, a university scholar and administrator, and a courtier and poet. One thing they had in common, besides a love of learning, was their attention to the art of astrology. And through their interest in astrology, they were all influenced by a 9th century Arab known in the West as Albumasar. His full name was Abu Ma'shar Ja'far ibn Muhammad ibn 'Umar al-Balkhi (787-886), and he was one of the most respected figures in the history of astrology.

Abu Ma'shar was of particular interest to Western Europe because he was a source for knowledge of and commentary on Aristotle when his writings reached Europe in the 12th century, brought back by the Crusaders. He offered so much more, however. His work blends knowledge of Greek science with Islamic doctrine, Persian chronology, Mesopotamian astrology, and hermetic traditions from Anatolia. He presented a unified approach to the knowledge of several cultures that lent weight to his work.

For instance, he uses the Biblical Flood as the focal point of his astrological tables. He calculates it at midnight on Thursday to Friday, 17-18 February 3101 BC. This date was not arbitrary, nor was it an indication that Abu Ma'shar believed in a short-lived Earth. He chooses the date because it is the start of the Hindu Kali Yuga (the "age of vice"; the last of four phases the world will go through). His knowledge and acceptance of Hindu chronology and its "Great Year" (composed of 360,000 years) is further shown when he calculated a grand conjunction of planets in 183,101 BC, and again in 176,899 BCE.

The Middle Ages loved "unified theories" that could reconcile different traditions to enhance understanding. Abu Ma'shar argued for the superiority of his chronological calculations because he made the year out to be 365.259 days long. Why was he so enamored of this number? Because "259" he explained was the minimum number of days for human gestation (8.6 months). It was obvious to him that he was onto something!

Unlike the hostility experienced by astrology from the University of Paris and others, who felt it was a way to contravene God's plan, or to know what should remain unknowable, Abu Ma'shar was able to give his astrology a veneer of respectability by acknowledging Islamic religious doctrine.