But paradoxically, conflict and conquest have also been the agents of peace. Over the millennia, the greatest intervals of peace were brought by the empires that took over large portions of the region. From the Macedonian conquest, with its Hellenistic civilization, through the Roman, Byzantine, Ottoman, Habsburg, Russian and Soviet empires, peace in Eastern Europe has come, ironically, at the tip of a sword or the barrel of a gun.

Tolerance did not always come arm-in-arm with peace. For every example of tolerance, there are many more examples of intolerance. The peace imposed on Eastern Europe by the conquering empires was relative -- and it was always given on the terms of the conqueror. We must understand it, not idealize it.

Those empires were shattered with the arrival of western nationalism during the 19th century -- and Eastern Europe and the world have not been the same since Nationalism began as a positive force -- it offered a new logic for the construction of democratic states. But nationalism turned out to be a double-edged sword; in the lands of tyrants, it has been destructive -- indeed, the most destructive force in human history, killing 75 million human beings between 1914 and 1945 alone. We must ask ourselves boldly and honestly: Is it not time to rein in the excesses of nationalism?