Saxe,, JEAN DE.—For a long time two astronomers of the Middle Ages were confounded under this name.
(I) JOANNES DANKO, or DE DANEKOWE, DE SAXONIA, composed (1297) the “Notulae super compotum”; there is also in Paris a copy of the Canons of Jean de Linieres made by him (1323).
(2) JEAN DE COUNNOUT (DE CONNAUGHT), called DE SAXONIA, was likewise a disciple and great admirer of Jean de Linieres, and a composer of various astronomical and astrological works. In 1327 he drew up the “Canones super tabulas Alfonsii regis Castellae”, of great and lasting fame; in 1331 he reviewed the “Introductorium ad judicia astronomiae” of Al-Kabici (Alchabitius). In 1355 he composed examples of numerical computation on the “Canons” of Jean de Linieres, later on his own “Canons”, to give the students of the University of Paris practice in the use of astronomical tables. The “Canones in tabulas Alfonsii” were printed following the “Alfonsian Tables” in 1483. The “Scriptum super Alkabicium” was published at Venice, 1489, 1491, 1502, 1503, and in Paris in 1520.
PIERRE DUHEM