De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres)

Savile’s attitude towards the heliocentric model of the universe put forward by Copernicus in De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) – ‘All the spheres revolve about the Sun as their midpoint and therefore the Sun is the centre of the universe’ – was not unusual for the time: he deeply respected Copernicus’s achievements as an astronomer but did not necessarily agree with his conclusions. Thus he taught the Copernican and Ptolemaic systems side by side, and was not unduly troubled by the fact that they contradicted each other.