This book is a thorough transatlantic study of the religious migration of one small group—the Schwenkfelders—from Silesia to Pennsylvania in the eighteenth century. It is based on a thorough reading of manuscripts and contemporary publications in German and English by and about Schwenkenfelders on both continents. Horst Weigelt, a religious studies scholar who has written prolifically in both languages about the Schwenkfelders, focuses here on risks and opportunities in this small religious migration. He uses the Schwenkfelder example to assess whether, and to what extent, religious group migration leads to the loss, transformation, or strengthening of faith and practice. In other words, since migration incurs risk to faith in order to search for opportunity to preserve or promote it, what, in this case, was the result? Weigelt argues that some Schwenkfelders abandoned their faith, while significant contact with diverse religious groups during and after migration led others to modify their beliefs and practices. The faith and distinct identity of those who remained behind was ultimately lost, while most in Pennsylvania experienced a deepening or strengthening of their faith and practice. In short, this is an example of how migration can help preserve a small religious group, as long as there is tolerance at their destination and group members are willing to adapt to new conditions.

The greatest strength of this book is its comparative perspective. In addition to tracing developments among the around two hundred Schwenkfelders who migrated to Pennsylvania, Weigelt follows up on the fate of those remaining in Silesia and Upper Lusatia. Pressure from the new Catholic government in Silesia, which brought in Jesuit missionaries to convert the Schwenkfelders, led to the migrations. A disproportionate number of those immigrating to Pennsylvania were leaders and young, healthy members of the Schwenkfelder communities. The loss of so much leadership and vitality hurt the remaining communities so much that their decline continued even after 1741 when the new Prussian government offered tolerance. Weigelt argues that the most capable emigrated to America, leaving behind the very young, old, or sick, who were unable to take advantage of Prussian tolerance to build or maintain viable communities with a recognizable Schwenkfelder identity. Thus, migration to North America killed the Schwenkfelder movement in Germany rather quickly, after 300 years of existence. Meanwhile, the group flourished in tolerant Pennsylvania, and while changing significantly, it learned how to maintain its separate identity, and ultimately became one of many churches in the American denominational landscape.

Weigelt's work on the Schwenkfelders leads one to compare them with other small religious groups who migrated from Europe to British North America. There were only a few hundred Moravians in central Europe during their migrations to the colonies, yet that group flourished on both sides of the Atlantic. Ultimately, however, the North American Moravians did eclipse those in Germany in number and influence, as with the Schwenkfelders, but those in Germany never died out, and eventually the North Americans themselves were surpassed by the number of Moravians in Africa. Of the German radical pietist groups, the Amish, Dunkers (Church of the Brethren), and the Ephrata (Pennsylvania) cloister movement more closely resembled the Schwenkfelder experience: in all three cases migration to Pennsylvania was followed by decline of the communities in central Europe. English Quakers, on the other hand, forged enduring transatlantic connections through their migrations, while the experience of the around 2,500 French Calvinists (Huguenots) who migrated from Switzerland and France to the colonies was altogether different: In this case, the migrants to America failed to maintain a separate identity in the long term, while those who stayed home did—both in Switzerland, where they were a majority, and in France, where they were not. Thus, there is much to ponder concerning the varied fates of transatlantic migrations of pietists in this era, and Weigelt's thorough work on the Schwenkfelders allows us to carefully consider that group as we do so.

Weigelt's assessment of risk and opportunity in small religious group migration is instructive, but other issues are also worth considering. For example, women experienced risk, opportunity, and the decision to migrate differently than men, and this was no doubt the case with Schwenkfelders. Also, the fate of a religious group is shaped not only by the decision to take risks and seek opportunity elsewhere (or not) but also by the changing landscapes of their homelands and new lands. The Schwenkfelders remaining behind faced confessionalization and secularization, which one way or another shaped social conditions and the religious life of nearly everyone in central Europe, while those who migrated to Pennsylvania became part of the denominational landscape of North America that was both tolerant and increasingly religious. These contrasting trajectories likely influenced the different fates of the Schwenkfelders. From their perspective, the grand decision to migrate to the diverse, dispersed, and tolerant American landscape of revivalism, or remain in Upper Lusatia and Silesia was dramatic. Those who remained withered under the twin pressures of confessionalization and secularization, which by the 1830s snuffed out this once vibrant radical pietist movement. Those who left responded to their new landscape by redefining themselves in contrast to the others (as Weigelt shows), even as they interacted with and were influenced by them.

The very act of redefining themselves represented change, as well as identify formation and preservation. As long as the American group ultimately developed into a church, which they did in the early twentieth century, they succeeded in maintaining their (changed) identity in the land of denominationalism, pluralism, and revival. In the end, as Weigelt shows, the Pennsylvanians became quite different from the Silesians in the early nineteenth century and what they had been in the sixteenth and seventeenth centuries. Thus, another key in this story of separate paths and outcomes, in addition to the decision to migrate and who made it, was the contrasting physical and cultural landscapes of the two places. In any event, with Weigelt's work we now have a much better understanding of the Schwenkfelder example, which can help us interpret these larger questions and developments.