whose most famous work The Conics was, until modern times, the definitive work on the conic sections: the ellipse, parabola, and hyperbola. He proposed the idea of epicyclic motion for the planets. His methods were close to introducing Cartesian coordinates, but at the time the Greeks had no notion of zero or negative numbers. Euclid, Archimedes, and Apollonius were pre-eminent in the period of the third century bc known as the Golden Age of Greek mathematics.