Kepler claimed to have had an epiphany on July 19, 1595, while teaching in Graz, demonstrating the periodic conjunction of Saturn and Jupiter in the zodiac: he realized that regular polygons bound one inscribed and one circumscribed circle at definite ratios, which, he reasoned, might be the geometrical basis of the universe.
Kepler hævdede at have haft en åbenbaring 19. juli 1595, mens han underviste i Graz og demonstrerede Saturn og Jupiters konjunktion i dyrekredsen; han indså, at regulære polygoner har en indskreven og en omskreven cirkel i bestemte forhold, hvilket han mente kunne være universets geometriske basis.