Al-Biruni

Abu Rayhan Muhammad ibn Ahmad al-Biruni was born on 4 September 973 in the outer quarter of Kath, then the capital of Khwarazm. His nisba comes from the Persian word birun, “outside”, and refers to that suburb; the town of Beruniy in Karakalpakstan now stands on the site of ancient Kath. His mother tongue was Khwarazmian, but he wrote mostly in Arabic, and some of his works in Persian.

As a young man he studied under the mathematician and astronomer Abu Nasr Mansur ibn Iraq, a prince of the Afrighid house. In 990, aged seventeen, he determined the latitude of Kath from the Sun’s midday altitude. In 995 the emir of Gurganj, Ma’mun ibn Muhammad, seized Kath and ended Afrighid rule, and al-Biruni had to leave his homeland; for a time he lived in Rayy, where he discussed observations with the astronomer Abu Mahmud al-Khujandi.

In 997 he observed a lunar eclipse at Kath and, by comparing his timings with those of Abu al-Wafa al-Buzjani in Baghdad, worked out the difference in longitude between the two cities. In the same years he carried on a well-known exchange of questions and answers with the young Ibn Sina on Aristotelian physics and the structure of the cosmos. Around 1000 he lived in Gurgan under the patronage of the Ziyarid ruler Qabus ibn Wushmgir, to whom he dedicated “The Chronology of Ancient Nations”, a comparative account of the calendars, eras and festivals of many peoples.

In 1004 he returned to Khwarazm and served at Gurganj at the court of the Khwarazmshah Abu al-Abbas Ma’mun ibn Ma’mun. The circle of scholars gathered there, which included Abu Nasr ibn Iraq and, for several years, Ibn Sina, is known in Uzbek historiography as the “Ma’mun Academy”. When Sultan Mahmud of Ghazni conquered Khwarazm in 1017, al-Biruni was taken to Ghazna with other Khwarazmian scholars and spent the rest of his life there.

Accompanying Mahmud on his campaigns in India, he learned Sanskrit and fixed the latitudes of a number of towns in the Punjab and Kashmir. Near the fort of Nandana he measured the dip of the horizon from a mountain top and calculated the radius of the Earth, arriving at a figure within a few per cent of the modern value. In 1025 he completed “The Determination of the Coordinates of Cities”, on the methods of mathematical geography, and in 1029 wrote “The Book of Instruction in the Elements of the Art of Astrology” in both Arabic and Persian.

In 1030 he finished “India”, an impartial account of the religion, philosophy, sciences, calendar and customs of the Indians. In it he also discussed the hypothesis that the Earth turns on its axis, noting that the phenomena of the heavens could be explained on that assumption as well. To Sultan Mas’ud, who came to the throne that year, he dedicated his principal astronomical work, “The Mas’udic Canon”. Under Sultan Mawdud he wrote a book on precious stones and metals, and in old age, with his eyesight failing, a work on medicinal substances, the “Kitab al-Saydana”.

In a list of his writings drawn up around 1036 he named 113 titles; scholars estimate his total output at about 146 works, most of which are lost. He died in Ghazna in 1048 (some scholars place his death after 1050). In 1957 the town of Shabbaz in Karakalpakstan was renamed Beruniy in his honour, and the Institute of Oriental Studies of the Academy of Sciences of Uzbekistan bears his name.