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Calendars in Antiquity and the Middle Ages


ERC Research Project


Archive for October, 2016

Al-Biruni and his world

Professor Francoisde Blois3 October 2016

The Workshop on “al-Biruni and his world” took place on Monday 15 February 2016 at UCL. There were six speakers.

François de Blois (UCL) spoke about “The new edition of al-Biruni’s ‘Chronology’: work in progress”. After an outline of al-Biruni’s life and personality he gave an overview of the manuscript tradition and the problems involved in producing a new critical edition of this important work.

Eleonora Bacchi (Bologna) spoke about “The manuscript tradition of al-Biruni’s ‘al-Qanun al-Masʽudi’”. She discussed the dating of some of the old manuscripts of al-Biruni’s big astronomical compendium and showed images of these manuscripts.IMG_20160215_132342

Raymond Mercier (Cambridge) gave a wide-ranging talk on “al-Biruni and the astronomy of ‘al-Qanun al-Masʽudi’”. After a detailed overview of the contents of the eleven books of this major work the speaker focused on a discussion of its astronomical content and of al-Biruni’s use of the work of his predecessors, especially Ptolemy and al-Battani. An examination of his mean parameters leads to the conclusion that his calculation of the mean motion of the sun is virtually identical to that of al-Battani. The planetary theory is taken entirely from the Almagest with a shift in meridian of 42;26 degrees corresponding the interval between Alexandria and Ghazna. But the daily motions of the outer planets are based on a fallacious recalculation. al-Biruni’s astronomical data differ strikingly from those of his older contemporary Ibn Yunus. Whereas Ibn Yunus’s parameters lead to a correct determination of planetary positions (according to modern theory) al-Biruni’s are wide of the mark. The speaker came to the conclusion that al-Biruni was a clever mathematician, but a mediocre astronomer.


Sacha Stern (UCL) spoke on “al-Biruni on the Jewish calendar: sources and authority”. The speaker took as his point of departure a passage in the “Chronology” (Sachau’s edition pp. 55-6; his translation pp. 64-6) which describes three different versions of the 19-year intercalation cycle as used by the Jews. The speaker compared this passage (written in the year 1000 CE) with three slightly older Jewish sources: first the Letter of the Babylonian Jews to their co-religionists in Palestine from the year 922 CE; then the calendar treatise of Joshua ben Allan from the early 10th century; and finally the Responsum of R. Hayya Gaon from 994/5 CE. These reveal varied intercalation schemes evidently related to those described by al-Biruni. In fact there is at some points a close literal agreement between the Arabic and Hebrew sources, suggesting their dependence on a common literary source.

1Carole Hillenbrand (St Andrews) spoke on “al-Biruni on Islamic history”. This talk focussed on the large extract from a lost work by al-Biruni contained (in Persian translation) in the final section of the history of the Ghaznavid ruler al-Masʽud by al-Biruni’s contemporary Bayhaqi. The extract shows al-Bayruni as a chronicler of intimate details of Ghaznavid court life in the first years of the 11th century.

IMG_20160215_165827The workshop concluded with an animated paper by Robert Hillenbrand (St Andrews) on “The miniatures in the Edinburg manuscript of al-Biruni’s ‘Chronology’”. The Edinburgh manuscript 161, dated 1307/8, is a richly illuminated and illustrated copy of al-Biruni’s book, a major example of Ilkhanid arts of the book. The talk concentrated on a detailed comparison of the pictures in the Edinburgh manuscript with Chinese paintings of the same period. The confrontation shows the strong dependence of the Ilkhanid painters on Chinese visual vocabulary, but in particular the clumsy and imperfect assimilation of Chinese techniques, for example in the use of perspective.