But his assent to this was only extracted from him in 1540 by the importunities of his friends, especially of his enthusiastic disciple George Joachim Rheticus (1514-1576), who printed, in the Narratio prima (Danzig, 1540), a preliminary account of the Copernican theory, and simultaneously sent to the press at Nuremberg his master's complete exposition of it in the treatise entitled De revolutionibus orbium coelestium (1543).
- Rheticus was the only contemporary biographer of Copernicus, and his narrative perished irretrievably.
RHETICUS, or RHAETICUS (1514-1576), a surname given to GEORGE JOACHIM, German astronomer and mathematician, from his birth at Feldkirch in that part of Tirol which was anciently the territory of the Rhaeti.
Rheticus now began his great treatise, Opus Palatinum de Triangulis, and continued to work at it while he occupied his old chair at Wittenberg, and indeed up to his death at Cassovia in Hungary, on the 4th of December 1576.
The Opus Palatinum of Rheticus was published by Valentine Otho, mathematician to the electoral prince palatine, in 1596.
The calculation of tables of the natural trigonometrical functions may be said to have formed the work of the last half of the 16th century, and the great canon of natural sines for every 10 seconds to 15 places which had been calculated by Rheticus was published by Pitiscus only in 1613, the year before that in which the Descriptio appeared.