All these events were significant. Even before World War II it was noted that competition in this area does not result in anything good (currency wars). Bretton Woods system also had its own weaknesses (periods of suspended convertibility) ... Europe sought to rebuild after the war so monetary collaboration was essential for this reason as well...

The 150 years from 1800 10 1945 were dominated by wars between the major European powers, particularly France and Germany.  Economic unification was viewed as a means to integrated these two countries and possible reduce the prospect of future wars.  US power and fear of the USSR provided further motivation. 

During the 1950s, the objective was initially to collaorate econonomically (there was also the objective from Federalists firm Benelux, Germany or Italy to collaborate politically), but not so much the objective to have a common curency. This objective cam later, afetr Bretton Woods collapse, during the early 1970s, when European currencies distributed between strong currencies (DM and Florin) with low inflation rates and weak ones (roughlky speaking the other ones including FF and £) with hight and variable inflation rates. Next steps (including the intermeduate regimes tested during the 1970s, 1980s, and early 1990s) where unsuccesfull attemp to stabilize the internal fluctuations of European currencies, considered at this time as an obstable to  development and exchange synergies. Adoption of Euro has been successfull: from a monetary point of view: Europe has now a striong currency... and no growth :-(