When the balance of power is shaken by war, forging a new one is unavoidable. Done well, years of peace and prosperity follow. Done badly, the plunge back to conflict is often unstoppable.  Sparked in Prague in 1618, between one-third and one-half of the population of Europe perished in the Thirty Years’ War. Initially a religious conflict within the Holy Roman Empire, it spiralled into a series of bewildering battles spanning much of the European mainland. Finally, in 1648, a comprehensive and lasting peace was forged at Munster and Osnabrück in the German province of Westphalia.  Broadly, the Peace of Westphalia…