The Thirty Years’ War was the most destructive war in European history. It killed 5 million people, or 20% of the population of the German states. For comparison, the Soviet Union lost 12% of its population in the Second Word War. The causes of the war are complex. In the nineteen century it was seen as simply a ‘religious war’. Writing in the 1930s, Veronica Wedgewood thought that it was a pointless war, and ‘confused...