The claim that the English Civil War pitted Christians against Christians is straightforwardly accurate. The conflict (1642–1651) was fought between the Royalists (supporting King Charles I) and the Parliamentarians. Both sides were overwhelmingly Christian. The Royalist side was largely Anglican, adhering to the Church of England, and even included some Catholic Royalists who fought alongside Protestants. The Parliamentarian side included Puritans and other Protestant factions. Both sides employed chaplains, held regular prayer services, framed the war in providential and biblical terms, and claimed God's favor for their cause. The UK Parliament's own historical overview notes that many historians now regard the Civil War as "English, or British, Wars of Religion." The academic literature confirms that religion was a central dimension of the conflict, with both sides drawing on Christian theology to mobilize soldiers and delegitimize their opponents. There is no significant non-Christian faction involved on either side; the war was fundamentally a conflict within a Christian society, between Christians who differed over theology, church governance, and the relationship between crown and parliament. Sources: UK Parliament, "Great rebellion, English Revolution or War of Religion?" https://www.parliament.uk/about/living-heritage/evolutionofparliament/parliamentaryauthority/civilwar/overview/great-rebellion/ ; University of Helsinki, "Religion and the Battlefield in the first English Civil War (1642–1646)" https://helda.helsinki.fi/items/8d677f3a-8616-4ed3-8636-367238cef294 ; Cambridge University Press, "The Curse of Meroz and the English Civil War," Historical Journal https://www.cambridge.org/core/journals/historical-journal/article/abs/curse-of-meroz-and-the-english-civil-war/DCA3A5243245DC6AF9FA019DEEE880F8