Felix Klein's name has long been identified with Göttingen mathematics, and rightly so, since he was the principal architect of its modernized community. In assuming that role, he also spared no effort in portraying himself as the apotheosis of that celebrated mathematical tradition, which came to full fruition after the turn of the century. His reputation as a great mathematician by then securely established, Klein focused his attention on various large-scale projects, leaving to others – notably David Hilbert and Hermann Minkowski – the responsibility of training younger researchers. Although by then only in his fifties, Klein already seemed an eminence grise to that flock of ambitious young men who encountered him. He was remembered by that generation as an aloof Olympian, an image that lived on through Richard Courant and Max Born, two central figures in the Göttingen community during the Weimar era who lost their positions when the Nazis came to power (see Part V). By the end of their 12-year reign, few of those who had known the young Felix Klein were still among the living.