The importance of Pappus for the development of mathematics

The author came from Numerical Geometric Integration (see [1], in collaboration with Christian Lubich and Ernst Hairer) to Geometry, on which he had the occasion to write, in collaboration with Alexander Ostermann, a recent text-book [2]. During this work he realized more and more the importance of Pappus. Pappus, who lived about 300 A. D. in Alexandria, was the last of the great Greek mathematicians. His Collection [3] was one of the very rare documents on later Greek mathematical achievements which had survived the long centuries of darkness, before mathematical research had again been taken up by the Arabs and the Renaissance scientist. As a consequence, his influence on today’s mathematics is enormous. This talk attempts to give some examples.