Religious intolerance ultimately led to conflicts that, when combined with international power struggles, became complex. The refusal of Philip II of Spain to countenance ancient Dutch freedoms and tolerate a diverse religious society led to an extended conflict referred to as both the Dutch Revolt and the Eighty Years' War. It overlapped with pre-modern Europe's most extensive and destructive war, the Thirty Years' War. Though sparked by a religious revolt by Bohemian Calvinists against Holy Roman Emperor Ferdinand II, the dispute rapidly lost its religious basis as it expanded into a European-wide superpower conflict.
In a war full of horrors, the depredation of soldiers on both sides was notorious. "The cruelty of the souldier towards the inhabitants of those countries, is inexpressible," wrote Philip Vincent in his account, which included gruesome illustrations to help convince readers.