The other, delivering the keynote speech, was Christine Lagarde, the managing director of the International Monetary Fund.

Ms. Lagarde’s presence reflected her close, longtime friendship with Mr. Schäuble. But it also was a confirmation of the enormous stature that Ms. Lagarde and the I.M.F. have acquired in Europe as a result of the euro crisis.

The I.M.F. has more say over crisis management than many euro zone members, and Ms. Lagarde has become a quasi head of state, whose views carry more weight than those of many elected leaders. Indeed, without the I.M.F.’s money and advice, the euro zone might have fallen apart by now.