The House of Wisdom and the translation movement

Part oneA caliph who wanted to measure the Earth

Around 830, teams of astronomers and surveyors sent by the caliph al-Ma'mun went out onto the open plains of the Middle East. Their task was to measure one degree of the Earth's curve along a line running north and south. From that, they could work out the size of the whole planet. Accounts differ on where each team stood and on the exact figure they reached, but the project itself is well remembered. It shows what kind of ruler al-Ma'mun was.

He was a son of Harun al-Rashid, and he had come to power the hard way, through a civil war with his brother that ended in 813. He ruled from Merv, in Khurasan, for six years, and then came to Baghdad in 819. From then until his death in 833 he made scholarship a matter of state. He listened to debates between thinkers of different views, he paid for observatories in Baghdad and on Mount Qasiyun near Damascus, and he asked for a new map of the known world.

Astronomy had everyday uses for Muslims. It helped fix the times of prayer, the direction of the qibla towards Makkah, and the start of each month. At the observatories, astronomers watched the sun, moon and planets over many months and produced a corrected set of tables, known as the Verified Tables, which later astronomers used and checked in their turn.

The revelation to the Prophet ﷺ began with a command to read, and Muslim scholars had always treated seeking knowledge as part of faith.

From the Quran

ٱقْرَأْ بِٱسْمِ رَبِّكَ ٱلَّذِى خَلَقَ ۝١ خَلَقَ ٱلْإِنسَـٰنَ مِنْ عَلَقٍ ۝٢ ٱقْرَأْ وَرَبُّكَ ٱلْأَكْرَمُ ۝٣ ٱلَّذِى عَلَّمَ بِٱلْقَلَمِ ۝٤ عَلَّمَ ٱلْإِنسَـٰنَ مَا لَمْ يَعْلَمْ ۝٥

¹Read, ˹O Prophet,˺ in the Name of your Lord Who created— ²created humans from a clinging clot. ³Read! And your Lord is the Most Generous, ⁴Who taught by the pen— ⁵taught humanity what they knew not.

The place most closely linked with his work is the House of Wisdom, Bayt al-Hikma. Its roots lay in the libraries of earlier caliphs, going back to al-Mansur and Harun, and under al-Ma'mun it grew into a centre where books were collected, copied, translated and studied. Historians still debate how it was organised and how much of it was a library, a workshop or a meeting place. No ruins have been found. What is certain is the work that was done in Baghdad in those years, and the people who did it.

Part twoThe translators

The main task was translation. Al-Ma'mun's agents searched for manuscripts and bought or borrowed them, including from lands under Byzantine rule. Euclid's geometry, the astronomy of Ptolemy, the medicine of Hippocrates and Galen, and the philosophy of Aristotle all passed into Arabic. So did works of Persian and Indian science. Ptolemy's great astronomy book was known in Arabic as al-Majisti, and its English name, the Almagest, comes from that word.

Many of the translators were not Muslims. Hunayn ibn Ishaq, born around 808, was a Christian physician from the city of al-Hira in Iraq. He travelled to find the best manuscripts of Galen, compared them, and produced translations that were famous for their care. With his son and his nephew he ran a workshop that turned out Greek medical books in Syriac, the language of many eastern Christians, and in Arabic. Thabit ibn Qurra, from Harran in northern Mesopotamia, was a mathematician and astronomer who both translated and wrote his own works. Qusta ibn Luqa, a Christian from Baalbek, did the same.

Muslim scholars took part as well. Al-Kindi, who lived from about 801 to 873, wrote on philosophy, mathematics, optics and music, and is remembered as the first great philosopher writing in Arabic. The three Banu Musa brothers, Muhammad, Ahmad and al-Hasan, grew up under al-Ma'mun's protection. They paid for translations, wrote on geometry, and compiled a book of ingenious mechanical devices.

The scholars were not content to copy. They tested what they read, and where Ptolemy's figures did not match what they saw in the sky, they corrected them. Readers in Baghdad could now compare Greek, Persian and Indian methods side by side. Because Arabic was spoken from Spain to Central Asia, a book written there could be read across the empire. Some Greek works survive today only because they were translated into Arabic at this time.

Paper made all this easier. Baghdad had copyists, and bookshops where readers met to talk. Writers such as al-Jahiz, who lived in Basra and Baghdad and wrote on animals, society and manners, found a public that would buy their books. A person did not need to be a prince to own a book any more.

Al-Ma'mun died in 833 while on campaign near Tarsus, on the Byzantine frontier. In his last years he also tried to impose one view on a theological question, a policy known as the Mihna, which is covered in a later chapter. His real legacy lay elsewhere, in a habit that outlived him. Caliphs, viziers and wealthy families kept paying scholars for centuries afterwards, and the work begun at Baghdad carried on in many cities.

The scholars of Baghdad did not stop at copying the ancient books. They tested them, corrected them and wrote new ones.

More on How to Muslim

• guide.howtomuslim.orgScience and IslamFaith and knowledge, side by side.

WatchThe lecture for this chapter

Lecture Al MuqaddimahHarun al-Rashid and al-Ma'mun, The Patrons of the Golden Age (opens on YouTube)

The mapWhere it happened

• Merv
• Baghdad
• Damascus (Mount Qasiyun)
• Harran
• Constantinople

This map is a simple sketch to help you picture where events took place. Positions, distances and borders are approximate, so please use it for reference only, not as an accurate map.

SourcesSources for this chapter