Built for cardinal Antonio Davia, it was donated by him to the Institute of Science in 1726.
It represents the Copernican Solar system with the Sun at the centre and the planets revolving around it and the Moon moving round the Earth. On the outside the Zodiac belt illustrates the various constellations.
It should be remembered that in those days any hint of Copernicanism was still censured by the Church. Despite the protection of powerful prelates, Manfredi himself had difficulty in publishing work connected, even non explicitly, to the motion of the Earth.
Anxious to avoid any trouble with the church authorities, the Administration of the Institute, notwithstanding Davia’s authority, gave orders that the sphere the cardinal had donated should be flanked by two other similar exemplars, representing the models of Tycho Brahe and Ptolemy. It is however uncertain whether these two spheres were ever actually built to the extent that there is no trace of their existence except the drawing of the Tycho model.
F. Farinelli (1979), p. 183.
G.G. Bolletti (1751), p. 112
Notizie dell’Origine e Progressi dell’Instituto delle Scienze di Bologna (1780), p. 186.