Roger Louis Billard 1922-2000
Roger Billard’s investigations into Indian astronomy marked a radical advance in our understanding of that long tradition. For so long people had assumed that there had been no serious observations underpinning the parameters in the numerous texts, this in spite of the fact that for so many centuries perfectly competent calendars had been calculated according to one or another of the various canonical texts.
Billard, an only child, was born
in Puteaux, in the outskirts of
However his youthful ambition was frustrated in
Immediately after the war,
however, he entered the École des Langues Orientales Vivantes in
He married Constance Ragunather,
a woman of Scottish and Indian parents, in 1949, and in the following year he
chanced to meet the distinguished orientalist Louis Hambis, which led to his
becoming in 1952 a member of the École Française d’Extrême Orient, and to his
appointment as Conservateur at the Musée Albert Sarreau in
He spent the next three years in
Up to this time the heavy
calculations which his investigations required were made with a Swedish desktop machine made by Odhner,
similar to the better known Brunschviga, one of those mechanical aids that so
many will remember from those years, when electronic calculation could only be
done on a large mainframe computer. From 1966 however he was able to make use
of the mainframe installed at the Collège de France. Without that support the
numerical results and graphs in L’Astronomie
indienne would have been impossible. That book appeared in 1971, and on its
publication he was awarded the Delalande-Guérineau prize by the Académie des
inscriptions et Belles-Lettres. In 1976 he was elected to the
In 1979, soon after his
retirement at age 55, he moved from
The response to his work was a grave disappointment to him. He presented his first article of 1956 to Otto Neugebauer, who was initially unimpressed, but who, after some correspondance, encouraged him to write an ampler account as a book. When eventually the book L’Astronomie indienne appeared, the response came this time not from Neugebauer, but in a review by David Pingree. This was wholly negative, and only served to confirm him in his feeling that people were entirely unprepared to understand his work.
In fact he was recognized by a handful of scholars. For example, by 1977, after my own appreciation had matured, I told B.L. van der Waerden, the distinguished mathematician and historian of astronomy, about Billard’s discoveries, and he showed at once a full and enthusiastic appreciation of its singular importance for the understanding of the history of Indian astronomy.
At the heart of this relatively straightforward scientific investigation, was the comparison between the mean longitudes of Sun, Moon and planets as calculated by modern procedures, with those calculated from a Sanskrit source. Such comparisons had been made earlier, notably by John Bentley, but without much success. Billard correctly put this failure down to the relative inaccuracy of Bentley’s astronomical calculations, and to the fact that fewer Sanskrit texts were available at that time. Both fields needed to mature further, and more especially, greater effort was needed with the extensive numerical calculations.
The results of his analysis of any individual canon were expressed graphically as a bundle of deviation curves, showing in the most dramatic instances, such as that of Āryabhaṭa, the tight convergence of the deviations at one date, proving that the canon was founded on very close observations at that date, with an exact reduction to mean longitudes. With other canons, such as that of the Brāhmasphuṭasiddhānta, the same approach showed that although the canon was not so well related to observations, at least it belonged to the time of the author. It was therefore not derived from Pitāmahasiddhānta contained in theViṣṇudharmottarapurāṇa, as some had supposed; that is to say, the section of that work entitled Pitāmahasiddhānta merely plagiarizes from the work of Brahmagupta. However, perhaps the discovery that was most remarkable, since it went against the tendency of the Sanskrit texts to be founded on observations at one particular date, was his demonstration that the canons documented in Lalla’s Ṣiśyadhīvṛddhidatantra were truly founded on a long time base, extending from the 6th to the 9th centuries. So it is thanks to Billard’s meticulous researches that we can now for the first time follow the development of Indian astronomy as a normal observational science.
It is true that researches of this kind, in which modern astronomical calculations are applied to Indian astronomy, have acquired a bad reputation, so many uncritical datings having been proposed. Billard’s work however shows that when both the Sanskrit scholarship and the astronomical science are sound, then results of real depth can be established. If the work has not been widely appreciated, it is to some extent because so many in the community of historians tend to lack a rigorous scientific formation, and also because so many are in thrall to the pronouncements of David Pingree. However, the book is completely self-contained, and it is open to anyone with basic programming skills to reproduce his results
In his last years he continued to develop programmes for the calculation of Indian dates, according to the many canons that he had studied. In this way he helped to interpret the dates found in hitherto unpublished Cambodian texts. These results will be published by Claude Jacques, of the École française d’Extrême-Orient, as Les sources de l’histoire du pays khmer. Symposium organisé par l’École pratique des Hautes Études (Section des sciences historiques et phlologiques) du 28 juin au 3 juillet 1993.
His health began to fail as a result of Parkinson’s disease from around 1985, although it was kept under fair control by medication. In the end he was a victim of cancer, and died on Dec 30, 2000. He is survived by his widow, his daughter Hélène, granddaughter Léa, and son-in-law Doron.
BEFEO = Bulletin de l’École française d’Extrême-Orient.
‘Perspectives nouvelles sur l'astronomie indienne’, Artibus Asiae, xix, 3/4 (1956), pp.186 - 196.
Rapport de travail 1959-1960, L’Astronomie indienne, BEFEO, tome li, 2 (1963), pp. 659 - 674.
‘Les cycles chronographiques Chinois dans les inscription Thaïs’, BEFEO, tome li, 1963, 403 - 431.
L’Astronomie indienne. Investigation des textes Sanskrits et des données numériques. Publications de l’École française d’Extrême-Orient, Volume lxxxiii, Paris, 1971.
‘L’Astronomie indienne. Résolution d’une énigme et mathémathique d’une histoire’, Revue du Palais de la Découverte. Février 1973, pp. 11 - 2.
‘L’Astronomie indienne. Résolution d’une énigme et mathémathique d’une histoire’, Sciences et techniques. Revue de l’Ingénieur. No. 6 nouvelle série 15 Sept 1973, pp 31 - 45.
‘Āryabhaṭa and Indian astronomy : an outline of an unexpected insight’, Indian Journal for the History of Science, xii (1977), 207 - 224.
present karaṇaratna’, BEFEO, lxxv,
1986, 21 - 35.
[Previously published in Archives Internationales d’Histoire des Sciences, 52, (2002, No.149) 355-359.]