Peter Furtado, editor of History Today, writing in the Times Higher Education Supplement(Dec. 12, 2003):

Historians have always been fascinated by wars. Thucydides and Xenophon saw war as the result of political calculation and shifts in the balance of power, although both considered the wars they described as cultural clashes between two distinct and ultimately antagonistic world-views - to Thucydides between the democratic Athenians and the conservative and oligarchic Spartans; to Xenophon between the imperial, oriental tyrannical Persians and the federal, freedom-loving, nationalistic and decent Greeks.

To Roman historians Livy and Caesar, war was a natural function of the state, something justified by the very successes in Roman arms that they chronicled. The historians and chroniclers of the Christian Middle Ages, led by the Venerable Bede, saw history as having a didactic meaning, tending to see the suffering caused by war as God's punishment for wickedness and success in war as a sign of divine favour.

These two approaches, the realistic and the moralistic - supplemented by the structuralist approach that argues that wars are an inevitable result of fundamental contradictions in the system of power - have dominated discussion up to our own day. Plus, perhaps, the cock-up theory. While long-term causes were popular in the Marxistic 1960s and 1970s, they have since fallen prey to revisionism: for example, the English civil war was seen by Marxist historian Christopher Hill in the 1960s to have had long-term economic causes and deep intellectual roots in the transition from a feudal society to a commercial one, whereas today most historians blame it on short-term miscalculations and point out that no one foresaw it, even 12 months before hostilities broke out.

Not surprisingly, the two wars that have seen the most debate over their outbreak are the two world wars of the 20th century. While Fischer blamed the German high command for challenging British supremacy and destabilising the balance of power in Europe, others saw the war as resulting from a calculated risk by Germany that got out of hand; a third approach takes the focus away from Germany and blames the intellectual and cultural environment of Europe, while a fourth suggests the entire thing could have been avoided if the British foreign secretary had played his hand more subtly in the summer of 1914. Of course, these do not have to be mutually exclusive.

This argument has a direct bearing on attitudes to the Treaty of Versailles, which itself is often seen as the contributory cause of the rise of Hitler and the return of war in 1939. Indeed, some historians prefer to consider the two wars as part of a single conflict interrupted by a 20-year truce. But the fact that the two major wars of the 20th century were started by Germany led some to seek the origins of the war in the bellicose character of the German nation. For most, the second war was fought to end Hitler's plan of continental domination and to avert the consequences of the Nazi-Soviet pact.

Fresh life has been breathed into all these questions by the war in Iraq, and historians have been as divided as any other group on its rights and wrongs. But they have probably been less noisy than in the debate on the "war on terror" in the aftermath of 9/11, when they debated the question of a historic "clash of civilisations" between Islam and the West, as Samuel P. Huntington had argued. The typical historian's counter to Huntington's assertions was a sceptical one, with an appeal to caution and complexity, and attention to the specifics of when, where, who and how.