Sphaera mundi

The treatise De sphaera or Sphaera mundi by the English astronomer and mathematician John of Holywood (13th century), written between 1212 and 1230, summarises ancient and medieval astronomical knowledge in four books. The Venetian edition of 1490, illustrated with diagrams of celestial orbits, depicts on its title page the allegory of Astronomy enthroned between the celestial muse Urania and Ptolemy.