At the end of 1991, after the Maastricht summit, we could reasonably have predicted that there would be two kinds of political problem generated by the euro. First, that if the euro-zone were in 1997, the first date at which it could have been launched, or 1999, when it did indeed begin, to spread beyond Germany, France, Belgium, Netherlands, Luxembourg and Denmark, then there would be good reason to wonder whether all members of the zone could withstand a single monetary policy. Meeting the convergence criteria specified in the Maastricht Treaty would not necessarily mean that there was sufficient convergence in macro-economic cycles to warrant having the same interest rates over the whole of the euro area.