The Middle East reminds us that there is nothing so unholy as a holy war. Europe learnt this in the 17th century. Confessional competition between Catholicism and Protestantism fused with temporal rivalry to provoke the Thirty Years’ War among the continent’s leading powers.
The fighting, bloodier than any previously seen, ended when raison d’état triumphed over theology. The Peace of Westphalia in 1648 marked the end of Europe’s great wars of religion. This should tell us something about the present conflict in Syria.
The wholesale slaughter that followed could not have been imagined in 1618, when mainly Protestant Bohemia rose up against the Catholic Holy Roman Empire. The subsequent wars — there were several — drew in Habsburg Spain and Austria, France, the Netherlands, Sweden, Poland, Russia, Denmark and the big German principalities. England, Scotland, the Ottoman Empire and Russia all claimed walk-on parts.