Catholic Encyclopedia (1913)/Jean de Saxe

For a long time two astronomers of the Middle Ages were confounded under this name.

(1) Joannes Danko

(Also DE DANEKOWE or DE SAXONIA). Composed (1297) the "Notulae super compotum"; there is also in Paris a copy of the Canons of Jean de Linières made by him (1323).

(2) Jean de Counnout

(Also DE CONNAUGHT or DE SAXONIA)

Jean de Counnout was likewise a disciple and great admirer of Jean de Linières, 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 Linières, 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.

BONCOMPAGNI, Intorno alle vite inedite di tre matematici (Giovanni Danck di Sassonia, Giovanni de Lineriis e Fra Luca Pacioli di Borgo San Sepolcro) scritte da Bernardino Baldi in Bulletino di Bibliografia e di Storia delle Scienze matematiche e fisiche, t. XII, 1879.

PIERRE DUHEM