Johannes de Sacrobosco
English astronomer and mathematician (fl. 13. century)
Johannes de Sacrobosco, also written Ioannes de Sacro Bosco, later called John of Holywood or John of Holybush (c. 1195 – c. 1256), was a scholar, Catholic monk, and astronomer who taught at the University of Paris.
He wrote a short introduction to the Hindu-Arabic numeral system. Judging from the number of manuscript copies that survive today, for the next 400 years it became the most widely read book on that subject. He also wrote a short textbook which was widely read and influential in Europe during the later medieval centuries as an introduction to astronomy. In his longest book, on the computation of the date of Easter, Sacrobosco correctly described the defects of the then-used Julian calendar, and recommended a solution similar to the modern Gregorian calendar three centuries before its implementation.
Very little is known about the education and biography of Sacrobosco. For one thing, his year of death has been guessed at 1236, 1244, and 1256, each of which is plausible and each lacking adequate evidence.
Place of birth
The country in which he was born is uncertain.
The public source identifies “Johannes de Sacrobosco” as english astronomer and mathematician (fl. 13. century). This brief keeps that definition visible, then builds a research path around Johannes, Sacrobosco and English.
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Biographical claims are most persuasive when dates, appointments and relationships can be traced to records created close to the events described. The source revision retrieved here is dated Jul 22, 2025. The linked authority identifier is Q433841. VIAF identifies the subject as 44151776764918011946. The Library of Congress control number is n84006968. 2 of 6 selected statements include explicit references; 4 carry qualifiers and 0 use preferred rank. The first chronological checks are 1195, 1256, 1236 and 1244.
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This entry incorporates text from “Johannes de Sacrobosco” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.