A 13th Century guide to the heavens
Ioannis de Sacro Bosco [c. 1195 – c. 1256] was a scholar, monk and astronomer [probably English] who taught at the University in
In around 1230 he wrote this authoritative medieval astronomy text Tractatus de Sphaera [On the Sphere of
the World]. It gives a
readable account of the Ptolemaic universe [the
universe according to the Hellenistic astronomer Claudius Ptolemaeus in the 2nd
century AD] that went on to become required
reading by students in all Western European universities for the next four centuries.
Though principally about the heavens it contains a clear description of the
earth as a sphere and its popularity shows the nineteenth-century opinion that
medieval scholars after this date thought the Earth was flat as a fabrication [Wikipedia]. Paris
This copy [photographed here] is dated 1577 and forms part of our Vaynor Collection; this consists of a number of 16th and 17th century astronomical works, including several of the writings of Galileo. The collection was formed and donated by John Herbert James of Vaynor [which is just north of
The condition of this book is excellent; the paper is bright and unmarked, robust to the touch and all the little volvelles [rotating paper wheel charts] still work perfectly.
It is bound in pure white vellum [calf skin] as are the majority of the Vaynor astronomical books which I always think gives them a very celestial look...
All photographs in this post taken by Squirrel Library.