Nicolaus Reimers Ursus · 1588
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Nicolaus Reimers Ursus (1551–1600) was a self-taught mathematician from Dithmarschen who later became imperial mathematician to Rudolf II. He published the Fundamentum astronomicum at Strasbourg in 1588.
The book sets out a new method of sines and triangles, with tables. It closes with a new hypothesis of the world system: a geo-heliocentric arrangement in which the planets circle the Sun, the Sun circles the Earth, and the Earth turns daily on its axis. Three folded plates accompany the text.
Tycho Brahe held that Ursus had taken the system from his papers during a visit to Uraniborg in 1584. The charge of plagiarism opened one of the bitterest priority disputes of early modern astronomy, to which Kepler’s Apologia pro Tychone belongs.
The source is the 1588 Strasbourg printing, from a copy in Copenhagen. A German translation exists; this is the first in English.