 Kepler published the third law, the so-called “harmonic law”, for the first time in his Harmonice mundi (1619), i.e., ten years later. In his Epitome, he provided a more systematic approach to all three laws, their grounds and implications (see Davis 2003; Stephenson 1987). In Book 5, chapter 3, as point 8 of 13 (KGW 6, p. 302; Engl. trans., pp. 411–12), Kepler expresses, almost accidentally, his fundamental relationship connecting elapsed times with distances, which in modern notation could be expressed as: