Many people assume the separation of church and state established in the US Constitution resulted from 16th- and 17th-century “religious violence” and “religious wars” in Europe. The wars of this period included the Thirty Years’ War (1618–1648) and the English Civil War (1642–1651).

These wars were foundational to the development of the political institutions of the West. They were part of a vast social/cultural/political process that ultimately replaced feudalism and the “divine right of kings” with the centralized, capital-based governments that dominate the world today.

The ferocious wars of these centuries made a deep impression on the collective memory of European people. Estimates of Central European deaths in the Thirty Years’ War run from 3 to 7 million (many of these resulting from starvation and disease among the civilian population). Deaths from war, disease, and starvation during the English Civil War have been estimated at around 800,000, or 4 percent, 6 percent, and 40 percent of England, Scotland, and Ireland’s populations respectively. Because nearly all of the participants in these wars had religious loyalties and convictions, religious feelings were often exploited by rulers. But religion was not the underlying motivation.

Two well-known examples involved the establishment of Lutheranism and Anglicanism. In the 16th century, Martin Luther’s reasons for breaking with the Catholic Church were theological, but the Reformation would have been quickly crushed if it hadn’t been supported by powerful European rulers whose motivations were primarily political and economic. King Henry VIII of England separated from Rome and formed the Anglican Church for pragmatic, nonreligious reasons—largely due to the refusal of the pope to grant an annulment of his marriage to Catherine of Aragon. He believed the Catholic Church was interfering with the internal affairs of his kingdom. He also wanted to nationalize the vast holdings of the Catholic Church in England to consolidate his power.

In The Myth of Religious Violence (Oxford Press), William Cavanaugh refers to recent scholarship to show that the underlying causes of the “religious wars” of the 16th and 17th centuries weren’t religious. Cavanaugh includes eight pages of examples, of which the following quotation is only the first:

If there truly were a war of all sects against all, one would expect that war would have broken out soon after Europe split into Catholic and Protestant factions. However, between the time that Martin Luther nailed his Ninety-Five Theses to the church door at Wittenberg in 1517 and the outbreak of the first commonly cited religious war—the Schmalkaldic War of 1546–1547—almost thirty years would pass. The Catholic prosecutor of the Schmalkaldic War, Holy Roman emperor Charles V, spent much of the decade following Luther’s excommunication in 1520 at war not against Lutherans, but against the pope. As Richard Dunn points out, “Charles V’s soldiers sacked Rome, not Wittenberg, in 1527, and when the papacy belatedly sponsored a reform program, both the Habsburgs and the Valois refused to endorse much of it, rejecting especially those Trentine decrees which encroached on their sovereign authority.” The wars of the 1540s were part of the ongoing struggle between the pope and the emperor for control over Italy and over the church in German territories (The Myth of Religious Violence, 143-44).

Cavanaugh provides massive documentation showing that rather than the state being the peace-making force that eventually solved the problem of religiously motivated violence, the process of centralizing public authority in a secular state was itself the most significant cause of violence. “There is a great deal of evidence to suggest that the transfer of power to the emergent state was a cause, not the solution, to the wars of the sixteenth and seventeenth centuries” (ibid., p. 162).

These wars replaced the religion of the church with the religion of the state.

The historical evidence renders . . . the idea that the modern state saved Europe from religious violence . . . unbelievable. State building . . . was a significant cause of the violence. An important aspect of state building was the absorption of the church by the state, which exacerbated and enforced ecclesial differences and therefore contributed to warfare between Catholics and Protestants. In the process, the state did not rein in and tame religion but became itself sacralized. The transfer of power from the church to the state was accompanied by a migration of the holy from church to state (ibid., p. 176).

(The reason many still consider religion the primary cause of war and violence is discussed in (Is Religion Evil?)