By Chris Morris
BBC Europe correspondent
The European Union passes another symbolic landmark on Monday with the launch of its first military mission.
Soldiers from neighbouring Greece are taking part
Known as Operation Concordia, it is putting flesh on the bones of the EU's ambitions to create a viable European defence identity.
It is neither the biggest, nor the most ambitious of missions - just 300 troops in Macedonia, to begin with, for just six months.
But if all goes well - and as the EU is taking over from a successful Nato mission, there is no reason why it shouldn't - then there will be more to come.
The EU already has its eye on the much larger peace-keeping operation in Bosnia, 12,000 troops are currently under Nato command.
Officials say future missions could take them to Africa or the Caucasus, once the EU's new rapid reaction force is up and running.
Europe has been split asunder by bitter disagreements about Iraq, exposing the fatal weakness of plans to create a common foreign policy.
But the Balkans is one place where the EU is making progress.