When the Library of Alexandria burned for the last time in the 7th century, and the Western Roman Empire had long fallen, the Western world lost almost all its Hellenistic heritage, including astrology. But astrology did not die; it traveled East.
This is the second article in a mini-series on the history of astrology. The first article traced its roots from Babylon to Alexandria. This one covers the period from the fall of Alexandria (around 600 AD) to the beginning of the Renaissance (around 1500 AD). The third will explore Eastern systems (Chinese and Indian) – parallel traditions that developed independently.
Without understanding this medieval transition, there is no explanation for why modern Western astrology uses Arabic terms (e.g., zenith, nadir, the names of many stars), why so many techniques bear Persian names, and why the Renaissance could happen. All this knowledge – preserved and developed – returned to Europe only in the 12th-13th centuries, ready for a new transformation.
The Fall of Alexandria and the End of the Hellenistic Era
Before discussing Arabic astrology, we must acknowledge what was lost. Between the 3rd and 7th centuries, the Hellenistic intellectual space gradually disintegrated. The Library of Alexandria burned several times – in the 1st century BC (Julius Caesar), in the 3rd century (civil wars), and finally in the 7th century (likely during the Arab conquest, though this episode is historically debated). Each time, less remained of the great collection.
Simultaneously, the Christianization of the Roman Empire after 313 AD (Edict of Milan) and the closure of pagan intellectual centers in the 5th-6th centuries (especially the closure of Plato's Academy in Athens in 529 AD) marginalized astrology in the Christian world. It continued to exist in the Eastern Roman (Byzantine) Empire, but in a more limited form.
By 700 AD, in the Latin West, astrology practically disappeared. Almost no one read Greek. No one could calculate a natal chart. Ptolemy, Dorotheus of Sidon, Vettius Valens – their works existed, but in few copies, in a language Europeans no longer understood.
And then, at the same time, something unexpected happened. In the East, in the new Islamic civilization, the Hellenistic heritage found new intellectual ground.
Baghdad: The House of Wisdom
In 762 AD, Caliph Al-Mansur founded Baghdad as the new capital of the Abbasid Caliphate. The choice of the moment for laying the city's foundations was astrological – made by two astrologers, Masha'allah ibn Athari (a Persian Jew) and Naubakht (a Persian). This was not mere symbolism. Al-Mansur literally believed that the city's inception moment would determine its fate.
Around 800 AD, Al-Mansur's grandson – Caliph Al-Ma'mun – founded the institution that would become the most important center of knowledge in the medieval world: Bayt al-Hikma – the House of Wisdom.
In the House of Wisdom, scholars from across the known world gathered – Muslims, Christians, Jews, Zoroastrians. Under the patronage of the Caliph, they began a monumental translation project. Greek texts were translated into Arabic. Indian texts – also. Persian texts – also. Ptolemy, Aristotle, Plato, Hippocrates, Euclid, Archimedes – all received Arabic translations. And along with them – all the astrological classics.
Astrologers who would shape the next millennia of Western astrology worked in the House of Wisdom. Masha'allah ibn Athari (754-813), who had already assisted in Baghdad's founding, wrote dozens of astrological works that would be translated in Europe centuries later. Abu Ma'shar (787-886) – called Albumasar in the West – wrote Introductorium maius ("The Great Introduction to Astrology"), which would become the most widely read astrological textbook in Europe from the 12th to the 15th century. Al-Kindi (c. 801-873) – known as "the philosopher of the Arabs" – wrote astrological works combining Greek philosophy with practical astrology.
Abu Ma'shar: The Most Influential Astrologer of the Middle Ages
Abu Ma'shar Ja'far ibn Muhammad deserves a separate section because his influence on Western astrology is greater than that of any other author between Ptolemy and Kepler. Born in Balkh (modern Afghanistan), Abu Ma'shar began his career as an Islamic scholar of hadith. Around his 50th year – by his own account – he turned to astrology under the influence of Al-Kindi. From then on, he dedicated his life to astrology and wrote numerous works.
His Introductorium maius (written around 850 AD) is a synthesizing work. Abu Ma'shar combined:
- Ptolemaic technical foundations (zodiac, houses, aspects)
- Persian astrological tradition (planetary periods, shahrengar – rulers of millennia)
- Indian astrology (nakshatras, specific techniques)
- His own philosophical innovations on the connection between the stars and the sublunary world
The result was the most comprehensive astrological textbook written to date. It was not just a compilation. Abu Ma'shar added original thought – especially in the concept of "great conjunctions" of Jupiter and Saturn, occurring once every 20 years and describing historical eras.
When Latin translators in Toledo began translating Arabic astrological texts in the 12th century, Abu Ma'shar was the first they translated. And for the next 400 years – from the 12th to the 16th century – Introductorium maius was the standard textbook by which every European astrologer was trained.
Al-Biruni: The Scholar Against Astrology
Not all Islamic scholars accepted astrology. One of the most important voices of skepticism was Abu Rayhan Al-Biruni (973-1048), a Persian scholar from Khwarazm.
Al-Biruni was one of the most versatile intellectual figures of the medieval world. A mathematician, astronomer, physicist, geographer, historian, linguist – he wrote in Arabic, Persian, Greek, Hebrew, Sanskrit, and Syriac. Between 1017 and 1030, he traveled throughout India, studying Indian culture, and wrote Tarikh al-Hind ("Book on India") – still one of the most important sources for Indian civilization of that period.
In his work Book of Instruction in the Elements of the Art of Astrology (1029), Al-Biruni did something paradoxical. He wrote a textbook on astrology – complete, technically precise, systematic. But at the same time, in other works, he publicly criticized astrology, claiming that many of its predictions did not come true, and that astrologers often drew wrong conclusions.
Why then write an astrological textbook? Because he believed that technical skills (calculating a natal chart, calculating transits, understanding planetary cycles) are valuable in themselves – regardless of interpretation. This is a stylistic position that modern astronomers working with astrological software would recognize.
Al-Biruni is important because he shows that Islamic astrology was not monolithic. There were proponents (Abu Ma'shar), skeptics (Al-Biruni), and many in between. This internal discussion within Islamic civilization itself is a useful model for modern astrology, which faces external skepticism.
Cordoba and Toledo: Gates to Europe
In the 9th century, Islamic civilization expanded to the Iberian Peninsula. Cordoba, the capital of Al-Andalus, became the second intellectual heart of the Islamic world – alongside Baghdad.
Between the 9th and 12th centuries, a vast intellectual community gathered in Cordoba and nearby Seville – Muslims, Jews, Christians. The Cordoba library reached 400,000 volumes at its peak – more than anything existing in the Christian West. Astrologers, philosophers, and scholars who would shape both Arabic and later European thought worked in Cordoba.
Two names are particularly important here. Maslama al-Majriti (c. 950-1007), who in Madrid (then Majrit) translated and adapted Ptolemy's Almagest and wrote Ghayat al-Hakim ("The Aim of the Sage"), a magical-astrological treatise known in Europe as Picatrix. And Ibrahim ibn Yahya al-Zarqali (Arzachel, 1029-1100), a Toledan astronomer-astrologer who created the famous Toledan Tables – astronomical tables used in Europe for centuries.
In 1085, a pivotal moment occurred. Toledo, until then a Muslim city, was conquered by Christian armies in the Reconquista. But unlike many other Christian conquests, Toledo retained a significant portion of its Muslim and Jewish population. The old libraries, madrasas, and intellectual centers remained.
And then, around 1130, the Archbishop of Toledo – Raymond de Sauvetât – founded something revolutionary: the Toledo School of Translators.
The Toledo School: The Latinization of Astrology
In the Toledo School, Christian monks worked alongside Jewish and Muslim scholars to translate Arabic texts into Latin. The process was usually three-step – an Arabic scholar translated from Arabic to spoken Spanish, a Jewish scholar wrote it down in Spanish, a Latin monk translated it into Latin. This was an incredible intellectual feat, and the result was massive.
Between 1130 and 1280, in Toledo and other similar centers (Palermo in Sicily, Barcelona), hundreds of Arabic astrological and scientific works were translated into Latin. Including:
- Introductorium maius by Abu Ma'shar – translated by John of Seville (c. 1133) and by Hermann of Carinthia (1140)
- Works by Masha'allah, translated by Adelard of Bath and others
- Toledan Tables by Arzachel, translated and adapted throughout Europe
- Picatrix by Maslama al-Majriti, translated in the mid-13th century
Simultaneously with these translations, the original Greek astrological classics were also translated – Ptolemy's Tetrabiblos, Dorotheus of Sidon, Vettius Valens – which the Arabs had preserved in Arabic. Thus, the Western world received both the Greek and the Arabic astrological heritage. Around 1200, the Latin West once again had everything – a technical foundation, authoritative textbooks, computational tables. Astrology returned, and in a richer form than Alexandria had.
Guido Bonatti: Medieval Europe Resurrects Astrology
With the influx of translated Arabic and Greek texts, a new generation of astrologers emerged in 13th-century Europe. The most important of them was the Italian Guido Bonatti (c. 1210-1296).
Bonatti was an astrologer of wars. He served as court astrologer to Frederick II Hohenstaufen (Holy Roman Emperor), to Guido Novello (Florentine political leader), and to various Italian city-states. There are famous legends that the Battle of Forlì in 1282 was won thanks to a specific astrologically favorable moment chosen by Bonatti. His Liber Astronomiae ("Book of Astronomy", actually astrology), written around 1277, is a systematizing work for all medieval knowledge. It combined:
- Ptolemaic foundations
- Arabic schools (especially Abu Ma'shar)
- His own practical experience as a court astrologer
Liber Astronomiae became the primary textbook for medieval European astrology. Around 1500, it was still being read, and in its translations (from Latin into Italian, English, German) it remained influential until the Renaissance. A curious fact: Dante Alighieri, in the Divine Comedy, places Bonatti in the eighth circle of Hell, in the fourth ditch – where the sorcerers and diviners are. Bonatti is depicted with his head turned backward – a punishment for trying to see the future. This is a critique of astrology that Dante makes – but also proof of how famous Bonatti was for Dante to include him personally.
Marsilio Ficino: The Bridge to the Renaissance
The end of the medieval period and the beginning of the Renaissance in astrology are personified by one figure – the Florentine Marsilio Ficino (1433-1499).
Ficino was a translator, philosopher, and astrologer. Under the patronage of Cosimo de' Medici, he translated from Greek into Latin the entire work of Plato (for the first time in Western history), plus the Hermetic Corpus – mystical-astrological treatises attributed to the legendary Hermes Trismegistus, and the works of Plotinus. This translation work was revolutionary. Before Ficino, Western Europe knew Plato mainly through late Byzantine and Arabic intermediaries. After Ficino – there was direct access to the original texts. This opened the Renaissance intellectual revolution.
In his own work – De Vita ("On Life", 1489) – Ficino wrote about how humans can harmonize their lives with astrological rhythms. He was not an astrologer-predictor. He was an astrological natural philosopher – astrology for him was a cosmological framework in which humans live, and for harmonizing with the cosmos, there were practical methods (proper diet, proper activities at proper times, proper music). Ficino is the last true medieval astrologer and the first true Renaissance one. With him, the medieval era ends. After him came the Renaissance geniuses – Paracelsus, Girolamo Cardano, Michel Nostradamus, Johannes Kepler.
What We Inherit Today
After this history, one question remains – what of this matters to a modern reader?
First, Arabic terms. When a modern astrologer speaks of "zenith" (the highest point), "nadir" (the lowest point), and dozens of stars like "Aldebaran" (from Arabic al-dabarān), "Algol" (al-ghūl), "Vega" (al-wāqi) – they are speaking Arabic without realizing it.
Second, forecasting techniques. A large part of modern predictive techniques – especially the Arabic parts (Pars Fortunae, Pars Spiritus, and dozens of others), profections, firdaria – come from the Perso-Arabic school, not the Greek. The Hellenistic revival, which we mentioned in the article on modern schools, is actually a revival of a large part of Arabic-inherited techniques, not just Greek originals.
Third, the very fact that Western astrology exists today is due to Islamic scholars. Without Baghdad and Cordoba, without the translation schools, without Bonatti and Ficino – astrology would have perished, along with the rest of the Hellenistic heritage, in the first few centuries after the fall of Rome. This must be acknowledged.
In the third article of the mini-series, we will turn to a completely different world – Eastern astrological systems. China developed its astrology independently of the Babylonian line. India has a hybrid tradition – common beginnings with Greek, but independent development over millennia. Both systems make the West seem much smaller than we tend to think.
Frequently Asked Questions
Why did Islamic scholars preserve astrology, but Christians didn't?
Because Islamic civilization did not have the theological opposition that the Christian West developed. In Islam, the study of natural laws – including the movements of celestial bodies – is religiously valid because it demonstrates the creative wisdom of Allah. The Christian West, especially after the 5th-6th centuries, became suspicious of pagan sciences. Only when Europe rediscovered Greek and Arabic texts in the 12th century did this position begin to soften.
Which Arabic astrological terms do we still use today?
Many. Zenith and nadir – Arabic. Many star names – Aldebaran, Algol, Altair, Betelgeuse, Deneb, Fomalhaut, Vega – Arabic. Almanac (astrological calendar) – Arabic. Pars Fortunae (Part of Fortune) – a Greek concept, but systematized and developed in the Arabic tradition. A large part of modern astrological predictive techniques have Arabic origins.
What is "Picatrix" and why is it important?
Picatrix is the Latin translation of Maslama al-Majriti's Ghayat al-Hakim – an Arabic magical-astrological treatise from the 10th century. Translated into Latin around 1256 in Toledo, it became the most important source of astrological magic in medieval and Renaissance Europe. It describes how to make talismans that correspond to astrologically favorable moments. Influential on Renaissance magic – Ficino, Agrippa, Paracelsus read it.
Why is Bonatti in Dante's Hell?
Dante had a theological position against astrology – not because he disbelieved in its efficacy, but because, in his view, it violated God's plan by attempting to predict the future, which belongs to God. Bonatti was the most famous astrologer in Italy during Dante's time, and thus received a symbolic place in Inferno. Ironically, Dante himself used astrological symbolism in the Divine Comedy – the poem's structure has astrological parallels. This is the standard medieval contradiction – astrology is criticized, but also used.
When did astrology return to Europe?
Gradually, between the 12th and 14th centuries. The first Latin translations of Arabic astrological works were made around 1130-1140 in Toledo. By 1200, Europe had a basic scientific and technical foundation. In the 13th century, the first European astrologers of a new generation appeared – Bonatti is a key figure. In the 14th-15th centuries, astrology was a standard part of university education (taught in Bologna, Padua, Paris). The Renaissance of the 15th-16th centuries brought it to the peak of its European influence.