1514-1574

German mathematician whose Narratio prima (1540) was the first published account of Nicolaus Copernicus's work. A disciple of Copernicus, Rheticus was instrumental in convincing him to publish De revolutionibus (1542). Rheticus also was first to relate trigonometric functions to angles rather than arcs of circles; prepared the best trigonometric tables of his time, which contained values for sines, tangents, secants, and their complementary functions to ten decimal places; and wrote a biography of Copernicus which has since been lost.