Emperor Rudolph II commissioned the astronomer Tycho Brahe and his successor Johannes Kepler to produce new planetary tables. The title page is striking: In the centre we see Tycho Brahe, an adherent of a geocentric view of the world, facing Nicholas Copernicus, a supporter of the heliocentric view. The title picture shows Tycho Brahe and Nicolaus Copernicus as representatives of the dispute over a geocentric versus a heliocentric world view.