"… History is again on the move," this famous remark of Toynbee was quoted by Raymond Aron remembering his own mood in Cologne and Berlin at the beginning of the 1930s. This moment was also the revelation of his "existential project": "On a beautiful day, walking along the Rhine, I thought I wanted to be both spectator and engaged. A spectator of history being made and engaged in this history in the making."¹