Brahmagupta

Brahmagupta was an Indian astronomer and mathematician. The Encyclopaedia of Islam names him as Brahmagupta of Bhillamala, a place it locates near Multan, and gives his birth as A.D. 598. ¹ He does not have a biography of his own in the articles read: they mention him only as the author of Sanskrit astronomical works that reached the Arabic-reading world. They give no date of death and say nothing of his family beyond the name of his town.

Two of his books are named. The Khandakhadyaka was written in A.D. 665; the article describes it as a practical treatise that gave material in a convenient form for astronomical calculation, based on a lost work of Aryabhata. ¹ The article on the science of the heavens ('ilm al-hay'a) adds that it belongs to the "Midnight School" of Aryabhata, as does the Persian Zij al-Shah. ² The other book is the Brahmasphutasiddhanta, which the same article dates to 628. ²

The article on 'ilm al-hay'a traces two routes by which his work reached Arabic. First, the earliest Arabic translation of a Sanskrit astronomical text was the Zij al-Arkand, made in Sind shortly after 117/735, and its elements derived largely from the Khandakhadyaka of 665. Two other zijes, the Zij al-Hazur and the Zij al-Djami, were based on the Zij al-Arkand and composed at Kandahar in the second/eighth century. ²

Second, the most important translation from Sanskrit into Arabic was that of a Mahasiddhanta of the Brahma school, which the article says was based chiefly on an earlier Paitamahasiddhanta and on Brahmagupta's Brahmasphutasiddhanta of 628. The occasion was the visit of an embassy from Sind to the court of the caliph al-Mansur at Baghdad in 154/771 or 156/773. The article reports that the translator is alleged to have been al-Fazari, who in his Zij al-Sindhind al-kabir mixed Iranian material with the Indian. ² The article notes that none of the works it lists in these sections survives, so its account "may well be in need of some revision" and "will not be free from controversy". ²

The article on al-Khwarizmi analyses his astronomical tables and finds a mixed character. Among their sources it names Indian handbooks for the methods of finding a planet's true longitude, and says the values of the planetary motion come from Brahmagupta. ³ Those tables are the Sindhind work the museum records as Zij al-Sindhind, which was later translated into Latin by Adelard of Bath.

From the articles read the museum cannot say where or when Brahmagupta died, whether any of his writing was available to Arabic readers in full, or how much of the Sindhind tradition was his rather than that of other Indian authors. The articles say the lost Arabic translations are known only through later accounts, so such questions stay open. Entries for his Sanskrit works are still to be added.