The Equatorie of the Planetis
1392 AD wrote
Describes an equatorium, which is an astronomical calculating instrument. It can be used for finding the positions of the Moon, Sun, and planets without calculation, using a geometrical model to represent the position of a given celestial body.
It includes six passages written in a substitution cipher of letters, numbers and symbols. Discovered in 1952 by Derek J. Price, and has sometimes been ascribed to Geoffrey Chaucer because of its language and handwriting. He maintained the possibility that Chaucer authored the Equatorie, possibly as the missing part of his A Treatise on the Astrolabe, which describes the astrolabe, and is sometimes cited as the first example of technical writing in the English language; the Equatorie seems to make direct reference to it.[1] Since then, most other scholars of the Equatorie maintain that the evidence for Chaucer's authorship is very weak, and that the case is not proven
