The astrologers of Baghdad

If you open a seventeenth-century astrology book — William Lilly's Christian Astrology, say — and follow its footnotes back, you keep arriving in the same place: Baghdad, in the eighth and ninth centuries. Much of what a traditional astrologer still does was gathered, argued over and written down there, in Arabic, by people from half a dozen peoples and three or four faiths.

This lesson is the story of that tradition: who they were, what they built, and how it reached the West. The rest of this part of the course takes up the techniques they left us one at a time.

A city founded on an election

In 762 the caliph al-Manṣūr chose a site on the Tigris for a new capital. The surviving accounts say that two astrologers, the Persian al-Nawbakht and the Jewish astrologer Māshāʾallāh, were asked to choose the moment for laying its foundations. Whether or not every detail is true, the story tells you how the new Abbasid dynasty saw astrology: as a respected science, close to the court, useful for beginning things well. (Choosing a moment like that is electional astrology — see Electional astrology.)

Many peoples, one language

"Arabic astrology" means astrology written in Arabic, not astrology done only by Arabs. The names show how mixed the world was:

• Māshāʾallāh (c. 740–815) and Sahl ibn Bishr were Jewish. Māshāʾallāh wrote the first Arabic treatise on the astrolabe, which Chaucer later followed for his own, and books on questions, elections and world events.
• ʿUmar al-Ṭabarī and Abū Maʿshar (787–886) were Persian. Abū Maʿshar, from Balkh in today's Afghanistan, became the most influential astrologer of the whole Middle Ages.
• Theophilus of Edessa was a Syriac Christian who served the caliphs as astrologer.
• al-Kindī, "the philosopher of the Arabs", was an Arab of noble family, and wrote on how the rays of the stars might act on the world.
• al-Bīrūnī (973–c.1050), from Khwarazm south of the Aral Sea, was perhaps the greatest scholar of them all. His Book of Instruction in the Elements of the Art of Astrology, written in 1029, is dedicated to a woman, his student Rayḥāna, and it opens with geometry, arithmetic and astronomy before it reaches a single judgement — he thought an astrologer should be able to calculate.

Three traditions poured into one

What made Baghdad remarkable was translation. Under the Abbasids, Greek, Middle Persian, Syriac and Sanskrit works were translated into Arabic, often more than once, and set side by side.

• From the Greek came Ptolemy and the Hellenistic astrologers — the houses, the aspects, the dignities, the lots. Dorotheus of Sidon reached Arabic through a Persian version, which is why so much early Arabic practice follows him.
• From Persia came the long time-measures of the world, the twenty-year meetings of Jupiter and Saturn, and the periods of life called firdaria.
• From India came astronomical tables and the idea of dividing the Moon's path into stations, which the Arabs matched to their own old star calendar to make the twenty-eight lunar mansions.

The astrologers did not simply stack these up. They compared them, chose between them, and built step-by-step methods a reader could follow — how to judge a planet's strength, how to tell whether a matter will be brought to completion, how to time a life.

What they added

You will meet most of these in the lessons that follow, so here they are only named.

• Horary, answering a question from the chart of the moment it is asked, set out by Māshāʾallāh and Sahl and later the centre of Lilly's work (Horary astrology).
• Elections, with the lunar mansions as one of their tools.
• The lots, multiplied from a handful to more than a hundred.
• The periods of life, combining the solar return, the annual profection and the firdaria.
• World astrology organised around the great conjunctions of Jupiter and Saturn and the chart of each year's spring equinox.

Their words are still in our mouths. Zenith, nadir and azimuth are Arabic; so are star names such as Aldebaran, Altair, Deneb and Fomalhaut. Lilly's almuten, the planet with most say over a degree, is the Arabic al-mubtazz, "the one who prevails".

The road west

In the twelfth century, in Toledo and elsewhere in Spain, and in southern Italy, scholars turned these books into Latin: John of Seville, Hugo of Santalla, Hermann of Carinthia, Adelard of Bath, Gerard of Cremona. The authors were renamed on the way. Abū Maʿshar became Albumasar, Māshāʾallāh Messahala, al-Qabīṣī Alcabitius, and Ibn Abī al-Rijāl, whose great compendium was a favourite of Renaissance astrologers, Haly Abenragel.

In the thirteenth century the Italian Guido Bonatti gathered much of this into one enormous handbook, and from there it ran on into the astrology of the European universities, of the Renaissance courts and, eventually, of William Lilly in Civil War London. When a modern traditional astrologer speaks of reception, of a planet being "peregrine", or of the lord of the year, they are speaking a language first written in Baghdad.

Astrology and faith

It would be wrong to picture the Islamic world as simply welcoming astrology. Philosophers such as Ibn Sīnā argued against its claims, and many religious scholars condemned the belief that the stars cause events — while honouring astronomy for the calendar, the times of prayer and the direction of Mecca. The astrologers usually answered that the stars are signs through which God works, not powers of their own.

That argument is worth keeping in mind, because it is close to the spirit of this course. A chart inclines; it does not decree. The tradition we are about to explore was, at its best, a disciplined way of reading the sky, practised by people who also argued, very seriously, about its limits.

Next, the Moon's twenty-eight stations: the lunar mansions, their Arabic names, and the Divine Names a great mystic set beside them.