Johannes de Sancto Bosco


The mathematician and astronomer Johannes de Sancto Bosco was born in Rastrick.

He was also known as Johannes de Sacrobosco, John of the Holy Wood, John Holywood, John of Halifax, and John Halifax.

He became a canon of the Order of St Augustine at the monastery of Holywood in Nithsdale.

He was educated at Oxford. In 1220, he went to study in Paris, and became a teacher of philosophy and mathematics – then Professor of Mathematics – at the University of Paris.

He promoted Arabic methods of arithmetic and algebra in his teachings, and in his De Algorismo, he discusses calculation with positive integers, with each of the 11 chapters dealing with topics such as addition, subtraction, multiplication, division, square roots and cube roots. He abridged The Almagest of Ptolemy.

In 1220, he wrote a book on astronomy entitled Tractatus de Sphaeri Mundi which deals with the shape and place of the Earth within a spherical universe, the various circles on the sky, the rising and setting of heavenly bodies from different geographical locations, and Ptolemy's theory of the planets and of eclipses. The book was used throughout Europe from the middle of the 13th century, and it was still the basic astronomy text until the 17th Century.

In 1232, he wrote De Anni Ratione which deals with time, the moon, and the ecclesiastical calendar. He maintained that the Julian calendar was 10 days in error and should be corrected. He suggested a reform of the calendar achieved by omitting one day every 288 years.

His other works include Tractatus de Quadrante on the quadrant, and De Computo Ecclesiastes.

In 1244 [or 1256], he died in Paris and was buried with a public funeral paid for by the University of Paris.

There is a lunar crater – Sacrobosco – named in his honour

See Wood

© Malcolm Bull 2021
Revised 15:13 / 15th May 2021 / 3616

Page Ref: MMS19

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