Al-Biruni's India, Completed About 1030, Devotes Half Its Pages to Indian Astronomy and Astrology Drawn From Sanskrit Texts Read With Pandits

Al-Biruni’s book on India, finished about 1030, is known in Arabic as Kitab tahqiq ma li-l-Hind, which can be rendered as an inquiry into what India holds, whether reason accepts it or rejects it. Its eighty chapters cover, in the words of the title E. C. Sachau gave his 1888 English translation, “the religion, philosophy, literature, geography, chronology, astronomy, customs, laws and astrology of India”. The translation spells the author’s name Alberuni.

E. S. Kennedy, who wrote the al-Biruni entry in the Dictionary of Scientific Biography, puts the book at about 700 folios, the largest of his works whose length is known. Noémie Verdon and Michio Yano, who published a new English translation of its fourteenth chapter in 2020, say that half of the book deals with astronomy and astrology. They call that material extremely precious to historians of Indian science, because it sheds light on Indian texts and authors that are otherwise not extant or unknown within Sanskrit literature.

A scholar from Khwarazm who ended up at Ghazni

Al-Biruni was born in 973 in Khwarazm, the region south of the Aral Sea, and was already an astronomer and mathematician of standing before he turned to India. In 1017 Sultan Mahmud of Ghazni took Khwarazm, and al-Biruni was among those carried off to Ghazni, Sachau writes in his preface. Kennedy ties his interest in Sanskrit to that move. By 1010 Mahmud’s armies had taken Multan and Bhatinda, and in 1026 they raided as far as Somnath. The scholar’s own travels were confined to the Punjab and the borders of Kashmir, in Kennedy’s account, and no dates for his visits survive. Eleven Indian towns appear in the book with latitudes that al-Biruni says he measured himself.

What he thought of the campaigns he did not disguise. The India says that Mahmud ruined the prosperity of the country and that the Hindus were scattered “like atoms of dust”, in Sachau’s translation. Sachau reads the cold way the book mentions the sultan as a sign that al-Biruni had no favour from him. The same editor judged that the book was written when Mahmud had been dead only a few weeks, with two of his sons contesting the throne, and that this is why it has no dedication, a reading Kennedy and MacTutor share. His verdict on the result was “a magic island of quiet, impartial research” in the middle of war.

Pandits, translations and how much Sanskrit he had

In his Arabic version of the Yoga Sutras, al-Biruni says he “went on translating from the Indian language books of arithmeticians and astronomers” before he turned to books of wisdom, in the Pines and Gelblum translation. According to Kennedy, his command of Sanskrit reached the point where, with the aid of pandits, he could translate several Indian scientific works into Arabic and the other way round.

Scholars differ on how far that Sanskrit went. Sachau says al-Biruni tried to check his pandits “by whatever Sanskrit he had contrived to learn”, and judged it next to impossible at the time to learn the language with full accuracy. To Verdon and Yano he was not a Sanskritist, though many of his identifications of Indian texts, authors and concepts remain valid today. The first chapter of the book explains the difficulty in his own words: a vocabulary of enormous range, a spoken form and a classical form, consonants that Arabic letters cannot write, careless copyists, and scientific books composed in metre to be learned by heart.

Several of his translations are documented. The Ghurrat al-zijat is his Arabic version of the Sanskrit handbook Karanatilaka by Vijayanandin of Varanasi, a karana being a compact manual of rules for computing positions and eclipses. The Sanskrit original is not extant, Kennedy says, but a manuscript of the translation sits in a library in Ahmedabad, and al-Biruni states that he changed nothing beyond adding worked examples that convert dates from the Shaka calendar. N. A. Baloch edited and translated it in 1973, Verdon and Yano report. A second documented translation is the smaller of Varahamihira’s two books on horoscopes, and a third, of the Pulisa and Brahmagupta texts, was still unfinished when he wrote.

Method counted for as much as reach in Sachau’s judgment. Al-Biruni went back to the Sanskrit sources, checked his pandits where he could, made new translations and tested the Indian astronomers’ figures by calculation, which Sachau called a scientific renaissance beside the earlier translators of Baghdad.

Five siddhantas, listed by an outsider

A siddhanta is a full treatise on mathematical astronomy. In chapter 14, in the Verdon and Yano translation, al-Biruni names five: the Surya, said to be by Lata; the Vasishtha, by Vishnuchandra; the Pulisa; the Romaka, by Srishena; and the Brahma, by Brahmagupta, son of Jishnu, of Bhillamala, a town he places between Multan and Anhilwara. All of them rest on an older book, the Paitamaha, he says. The Pulisa, in his account, is named for a Greek from a city he takes to be Alexandria, and Romaka comes from the Roman empire. Several cities carried the name Alexandria, Verdon and Yano note.

Varahamihira’s Pancha-siddhantika, he adds, does not live up to its title: it is not better than the five, and the name only counts them. The Varahamihira article on this site covers that book. He had copies of only two of the five, the Pulisa and Brahmagupta’s, and he lists the twenty-four chapter titles of Brahmagupta’s work. A comparison with the twentieth-century Sanskrit edition of the Brahmasphutasiddhanta, made by Verdon and Yano, shows that the text he knew was arranged differently: its chapter on the shape of heaven and earth comes first, whereas it is the twenty-first in the printed Sanskrit text. For the man and his rules for zero, see the Brahmagupta article.

The same chapter runs through the shorter manuals and their authors: Balabhadra, Vijayanandin, Vateshvara of Nagapur, Utpala of Kashmir, Manjula, and the Dashagitika and Aryashtashata of Aryabhata, which he treats as two separate works. Pingree’s Census of the Exact Sciences in Sanskrit has no entry for the Karanasara of Vateshvara and no information on a book by Lokananda or on one by Bhattila, all of which al-Biruni names, as Verdon and Yano record.

A round earth, argued in Indian words

Chapter 26 gathers what the Indian astronomers wrote on the shape of the world. Pulisa is quoted as saying that if the earth were not round, the latitudes of different places and the difference between winter and summer days could not exist. Aryabhata, Pulisa, Vasishtha and Lata agree, al-Biruni reports, that when it is noon at Yamakoti it is midnight at Rum and dawn at Lanka, which, in Sachau’s translation, “is not possible if the world is not round”. Brahmagupta argues from the rising of the same star above opposite horizons at different places, and Varahamihira holds that all things perceived by the senses bear witness to the globular earth.

As the chapter ends, al-Biruni remarks that these ideas are the elements of astronomy set out in the first chapter of Ptolemy’s Almagest, though not worked out in the same scientific form.

Does the earth turn? What he copied down

At the end of the same chapter al-Biruni takes up whether the earth moves. Brahmagupta is quoted on a view held by the followers of Aryabhata, that the earth turns and the heavens stand still, and on the objection raised against it, that stones and trees would fall off. Varahamihira’s reply to those who say the earth makes the daily motion is given as Brahmagupta cites it: a bird that flew west from its nest would never get back. The article on Aryabhata’s turning earth on this site gives the Indian side of that debate.

His own comment is careful. A turning earth does not weaken the value of astronomy, he writes, because every astronomical appearance can be explained as well on that theory as on the other, but other reasons make it impossible. The question is most difficult to solve, in his words, and he says he wrote a book on it, the Key of Astronomy. Sachau adds that the passage may be confused in places, perhaps through the translator’s fault.

Eighteen number names and the signs he praised

In chapter 16 al-Biruni records that he had asked people of many languages for the names of the orders of numbers and found that no nation went past the thousand, the Arabs included. The Hindus, he writes, name eighteen orders, from one up to parardha, with the help of the grammarians. His list gives the lakh as the sixth order and the koti, the crore, as the eighth. Some Hindus add a nineteenth, bhuri, he notes, and others stop at the koti. Aryabhata of Kusumapura is cited for a set of names.

On the signs themselves he writes, in Sachau’s rendering, that the numerals “we use” are derived from the finest forms of the Hindu signs. MacTutor gives another English version of the same sentence, a selection of the best and most regular figures in India. The shapes vary from region to region, as the letters do, he adds, and people in Kashmir numbered the leaves of their books with signs that looked to him like drawings or like Chinese characters. MacTutor reports that historians trace the Indian numerals to the Brahmi numerals of about the middle of the third century BC, and that the Nagari forms al-Biruni saw grew out of the Gupta ones from about the seventh century AD. The article on zero covers the place-value system behind them.

What he admired and what he faulted

Where he found Indian work good, he said so. Sachau cites his remark that the builders of ponds at holy bathing places had reached such a degree of art that Muslims who saw them wondered and could not describe them, much less build the like.

Disagreement got the same directness. Sachau lists his complaints that Brahmagupta treated Aryabhata unjustly and rudely, that some sentences in Varahamihira sounded to him like the ravings of a madman, though an esoteric meaning might lie behind them, and that he had no patience for the Indian pursuit of alchemy or the long-windedness of verse authors. Where he faulted an Indian custom, adds Sachau, he usually turned to compare an Arab custom of the same kind. Sachau’s preface counts about twenty books by al-Biruni on India, while MacTutor counts twenty-seven, so the tally depends on what is included.

Why historians still read it

In 1888 Sachau judged al-Biruni’s account of chronology and astronomy more complete and accurate than any given before it, and found no more original work in the field after al-Biruni’s death. That was Sachau’s verdict. Verdon and Yano, writing in 2020, put the weight on something more specific: the book’s testimony about particular Indian texts and authors. One more detail comes from Kennedy, who says the Ghurrat al-zijat follows methods common to medieval Indian astronomy but uses parameters that match no Sanskrit document that survives.

The date of his death is not settled. Sachau and MacTutor give 1048, while Kennedy and Bosworth place it after 1050 because his last book says he had passed eighty. Sachau’s Arabic edition of the India appeared in 1887 and his English translation in 1888, with a new edition in 1910, and a revised Arabic edition was published at Hyderabad in 1958. Verdon and Yano based their 2020 translation of chapter 14 on that Hyderabad text and corrected Sachau’s wording in places with the help of Pingree’s census.