Although Brandenberg-Prussia became predominately Lutheran during the Reformation, its confessional status was thrown into turmoil in 1613 by the conversion of Elector John Sigismund (the sovereign of the territory) to Calvinism. He then set about cleansing houses of worship of "the dirt of papal idolatry", including altars, baptismal fonts, crucifixes, and artwork. Strangely enough, the Elector naively assumed that his subjects would enthusiastically support these actions, as he believed the superiority of the Reformed faith was self-evident. But his plans for a "second Reformation" were met with stiff, and sometimes violent, opposition from both the nobles and the general populace. According to Clark, the conflict between the Calvinist and Lutheran camps centered on two issues: liturgy and the sacraments.
"[The conflict] was in part an aesthetic issue: to the colorful extravagance of a Lutheran church interior, with its candles and images graven and painted glowing with reflected fire, the Calvinists opposed the white space of a purified church, suffused with natural light. There was also an authentic apprehension that Catholicism remained a latent force within Lutheranism. A particular focus of concern was the Lutheran communion rite; Elector Sigismund objected to Luther's doctrine of the real presence in the Lord's Supper, calling it a 'false, divisive, and highly controversial teaching.' In the words of the Calvinist theologian Simon Pistoris, author of a controversial tract published in Berlin in 1613, Luther 'derived his views from the darkness of the papacy'... In other words, the Reformation remained incomplete."
Much to Sigismund's dismay, the people of Brandenberg-Prussia were rather attached to their ornate churches and communion rites, and thus there was no "second Reformation". From that point forward the monarchy of Prussia, along with most political elites, were Calvinist, while the remainder of the nation remained staunchly Lutheran. This was an awkward situation, to say the least, and to help ease the tensions the Prussian rulers to become some of the earliest advocates of "generic Protestantism". Their efforts culminated in the forced merger of the Lutheran and Calvinist churches into a single Prussian "evangelical-Christian church".
"The king himself [Frederick William III] was the chief architect of this new ecclesiastical entity. He designed the new United liturgy, cobbling together texts from German, Swedish, Anglican, and Huguenot prayer books. He issued regulations for the decoration of altars, the use of candles, vestments and crucifixes. The aim was to create a composite that would resonate with the religious sensibilities of both Calvinists and Lutherans. It was a further, final chapter in the long history of efforts by the Hohenzollern dynasty to close the confessional gap between the monarchy and the people."
As before, the King's designs aroused considerable anger amongst the people, who (justifiably) felt that their religious heritage was being stripped away. Several thousand "Old Lutherans" fled the country for North America and Australia, where they established confessional Lutheran churches like the LCMS.
If you're still reading, you might be wondering why this long story is relevant for us today. After all, such intense confessional antagonism is largely a thing of the past. The ELCA, for instance, has established full communion, including altar and pulpit fellowship, with several Reformed churches - PCUSA, UCC, and the Reformed Church in America. And no one seems scandalized by the fact that these churches do not believe in the real presence. That's because the real battle within Protestantism these days is between liberal and conservatives, and not between Lutherans and Calvinists. Thus, it's relatively easy for the ELCA to make common cause with mainline Presbyterians, even though the divide between Lutheran bodies like the ELCA and LCMS remains as wide as ever. But is it wise for the ELCA to enter into full communion with Reformed bodies that, while culturally similar, are theologically quite different? Likewise, is it prudent for more "confessional" Lutherans to mimic the behavior and attitudes of Southern Baptists?
Sadly, the generic Protestantism advocated by the Prussian kings, and resisted by their subjects, has become a reality for many Lutheran churches in America, both liberal and conservative. I wonder if this situation is a reflection our misplaced priorities, our tendency to put cultural issues ahead of theological ones. In the end, don't matters of sacramentology and liturgy, or predestination and atonement and Christology, lie at a more fundamental level of doctrine than homosexuality or the ordination of women? Surely they do, but it's the latter set of issues that stir the strongest emotions. Hence the temptation, as old as Christendom itself, to compromise one's theological heritage to secure political and cultural allies.