Giuseppe Piazzi (1746-1826), Italian astronomer and discoverer of the asteroid Ceres. Born in Valtellina, Italy, Piazzi taught philosophy as a monk before developing an interest in astronomy in middle age. In 1801, he discovered Ceres, the largest of the asteroids (minor planets which orbit between Mars and Jupiter), naming it after the goddess of agriculture. In 1814, he published a catalogue of 7646 stars. In this work he noted that proper motion (the movement of stars relative to one another rather than due to the Earth's rotation) was a feature of nearly all stars rather than just a few.