1656 SPHAERA by Johannes de Sacrobosco ANTIQUE illustrated ASTRONOMY

Johannes de Sacrobosco (1195-1256)

 Sphaera

Leiden: Johannem Elsevirium; 1656

bound in modern half calf and marbled paper boards, gilt title to the spine

 octavo

Illustrated with woodcut engravings

Ex libris Professor, Astronomer, Historian & Bibliophile Owen Gingerich.

Size 4 by 6 1/4 in.

Text in Latin
=================================
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.
===================================