Europe has a very long history of banking, but at the moment when the Euro was created, most of the obliterated national currencies were weak, reflecting distrust towards their overlords. Switzerland, the country with the strongest national currency in Europe, never felt compelled to join the bloc.
Historically, authoritarian countries tend to go bankrupt over war expenses, democratic countries over handouts. The British pound was strongest at the time when the country was somewhat semi-democratic, neither-nor. But that is a very unstable configuration.
Pick your poison.