This handsome volume is a pleasure to handle. Its crisp pages and elegant font are complemented by the precise maps and very well-described illustrations. The latter include reproductions of early modern images and photographs taken recently, some by the author, for whom the book is clearly a labour of love. The attractive presentation is enhanced by the clarity of the work's structure. The brief first part provides a general introduction to the Commonwealth and its confessions in the sixteenth and seventeenth centuries. This makes no new arguments of its own. Indeed, it repeats a controversial textbook concept of ‘Polonization’ (pp. 9–14) which was in reality a complex cultural and linguistic phenomenon. Nevertheless, this part will be of use to readers unfamiliar with Poland-Lithuania. The weighty second part, devoted to the Reformed Churches, contains five chapters which respectively explore the stages by which a distinct ecclesiastical polity took shape: the development of Reformed liturgy; the workings of Church discipline; the Reformed ministry; and emergent patterns of piety. In turn the third part of the book investigates people – the Reformed faithful. Most, but not all of the surviving evidence concerns noble families and this is understandably reflected in the many fascinating life stories and spiritual journeys which the author has illuminated. He treats seriously the motivations of those who converted to the Reformed Churches, as well as those who left their fold during the course of the century under consideration. Particularly noteworthy is the chapter concerning women, who in the later decades covered by the book often staunchly maintained their Calvinist faith when their husbands or children had converted to Roman Catholicism. Another highlight is the ‘fishing in Lutheran waters’ conducted by Calvinist pastors and patrons especially in the Royal Prussian cities of Gdańsk (Danzig) and Toruń (Thorn) and their rural hinterlands.

The thirteenth chapter confronts the prevalent historiographical narratives of the ‘failure’ and ‘weakness’ of the Protestant Reformation in Poland-Lithuania by homing in on ‘the ambiguity of numbers’ as well as the comparative frames. Bem argues that expectations need to be adjusted. The appeal of Calvinism crossed all social boundaries, at least where Catholicism was effectively suppressed for several generations. Some thriving Reformed communities, such as Leszno and Kiejdany (Kėdainiai), put down deep and enduring roots. Elsewhere, there was insufficient time; far less than in the Dutch Republic. The point is developed further in the conclusion. Bem rejects the charges of ‘tepid faith’, theological shallowness and the tendency to reduce explanations of the growth and retreat of Protestantism in the Commonwealth to socio-economic factors. His revisionist thesis amounts to more than a re-evaluation. He makes the case that theologically and organisationally, Polish-Lithuanian Protestantism long remained decentralised and highly fluid. Overlaps remained between Calvinism and Unitarianism, while the Bohemian Brethren broke with neither Calvinism nor Unitarianism until the beginning of the seventeenth century. These factors also help to explain the lasting territorial distinctiveness between the self-governing Reformed Churches in the provinces of Greater Poland and Lesser Poland, and in the Grand Duchy of Lithuania. Attention to discipline and liturgy helped forge a more united and distinctly Calvinist Reformed Church in the first few decades of the seventeenth century, culminating in the hitherto underestimated General Convocation held at Włodawa in 1634. But, within a generation, Protestants were scapegoated for the disasters that inundated the country: ‘the theological and liturgical bloom of the Commonwealth's Calvinists arrived just before their catastrophe began’ (p. 283).

The book is based on a great many primary and secondary sources, in several languages, but the lengthy bibliography contains some less welcome surprises. Unpublished (manuscript) and published primary sources are not distinguished, although unpublished and published secondary sources (literature) are separated. Moreover, an edition of Calvinists’ testaments has been misplaced in the secondary, rather than the primary sources. Rather embarrassingly, we find Janina instead of Jolanta Dworzaczkowa, and Daniel, rather than David Frick. The copious sources are a stern test of Bem's gifts of nuance and sensitivity. One example must suffice here. On p. 170 he quotes the convert from Orthodoxy to Calvinism, Fedar Jeŭłašeŭski (Teodor Jewłaszewski), a client of the arch-Catholic Mikołaj Krzysztof Radzwiłł, who recorded his stay in the Lithuanian capital of Viĺnia (Vilnius, Wilno). This memoir, considered a monument of Belarusian (or Ruthenian) literature, has been repeatedly edited, translated and published. Bem chose the 1860 translation into Polish from the original manuscript, rather than the later bilingual Belarusian and English edition by Fr Alexander Nadson, based on a nineteenth-century edition from a seventeenth-century copy. Nadson translated ‘бовем на он час разность веры не чинила наймнейшой розности приятелской’ as ‘For at that time difference of religion was no obstacle to friendship’, whereas Bem rendered the Polish ‘Albowiem naonczas różności wiary nie czyniły żadnego poróżnienia w przyjacielskiej miłości’ as ‘those days when difference in faith made no difference in friendly love’. It would seem that Bem was closer, but the question remains of what Jeŭłašeŭski might have meant by ‘faith’ and ‘religion’.Footnote ¹

Kazimierz Bem is a full-time pastor of the Congregational Church in Massachusetts. His unconcealed sympathies and convictions have not hindered him from writing the first modern historical synthesis in any language of Calvinism, broadly understood, in the entire Polish-Lithuanian Commonwealth. It can be recommended to all scholars and advanced students interested in the history of the Reformation in Europe.