Banca d'Italia, Roma, Italy Keywords Keynesian economics, Agreements, Monetary policy Abstract The Bretton Woods agreements set up the post·war monetary order on the basis of fixed exchange rates and autonomous national economic policy. Changes in parity were a110wed in the case of fundamental disequilibrium, but this concept was not defined, promoting a lengthy but sterile debate. This paper, after reviewing the main features of the discussion, anafyzes Keynes's overlooked contribution, which helps to clarify the issue at stake.