"Most obvious to historians is the part tribal and later communal differences have played in the violent conflicts that have been Europe’s default setting. These conflicts emerged from the Middle Ages as an ingrained, almost ritualized, addiction to war, practised by youths mostly still in their teens and twenties, men such as Clovis, Frederick II of Germany, Edward III of England, Charles V of Spain, Louis XIV and Napoleon. At this level, Europe’s story has been a tragedy of competing virilities. Each of the treaties that have waymarked history–Augsburg, Westphalia, Utrecht, Vienna, Versailles–has struggled to keep the peace but has done so for little more than two generations before war resumed. Even Potsdam in 1945 lasted only until the fall of the Soviet Union in 1989. Now the conspicuous lack of a post-cold-war settlement is putting Europe’s diplomacy under renewed strain. The continent’s DNA seems to allow people to live calmly with each other only as long as the memory of the last bout of bloodletting survives. A note of wisdom from the past might be that of the dying Louis XIV, ‘Above all, remain at peace with your neighbours. I loved war too much.’ Whether Europe’s belligerence can be attributed to the fractiousness of its original tribes I cannot tell."