A deadly continental struggle, the Thirty Years War devastated seventeenth-century Europe, killing nearly a quarter of all Germans and laying waste to towns and countryside alike. In a major reassessment, Wilson argues that religion was not the catalyst, but one element in a lethal stew of political, social, and dynastic forces that fed the conflict--a conflict that ultimately transformed the map of the modern world.

The shared history of Christianity and Islam began, shortly after Islam emerged in the seventh century A.D., with a question: Who would inherit the world of the Mediterranean? Sprung from the same Abrahamic source, the two faiths played out what historian O'Shea calls "sibling rivalry writ very large." Their clashes on the battlefield were balanced by long periods of coexistence and mutual enrichment, and by the end of the sixteenth century the religious...