Bremen has not fared particularly well in Anglophone historiography of the Reformation period. The city on the Weser has been overshadowed by its mightier neighbour Hamburg to the north-east or the bustling urban centres of the Low Countries to the south-west. Its geography, though, is precisely the reason for the region being such a fascinating target of study. In the Middle Ages Bremen was one of the critical provinces of the imperial Church, but with the coming of the Reformation, the archdiocese found itself in a difficult position. Caught between the Lutherans of the Baltic and the Calvinists of the North Sea, Bremen straddled an awkward confessional divide. Though its archbishop, the rock-ribbed Christoph von Braunschweig-Wolfenbüttel, did not desert Rome, its canons did, and by the 1530s the region had defected to the Lutherans. The growing influence of Dutch merchants on the city's mercantile elite pushed Bremen towards the Calvinists by the 1560s. The cathedral itself became a symbol of Protestant stalemate. The Lutheran canons of the cathedral, angry and upset with the Reformed leaders of the municipality, simply shut and locked its doors in 1561, and for nearly eighty years the massive medieval monument remained closed to the public. This is all background material for Leo van Santen's fascinating monograph on one of Bremen's most important figures of the early seventeenth century, Ludwig Crocius, a gifted leader who sought to mediate tensions between Lutheran and Reformed communities.

Born in 1586 in the spa town of Laasphe in what is today North Rhine-Westphalia, Ludwig Crocius came from two generations of Lutheran pastors. Both, though, were mild and favoured a Melanchthonian vision of reform. As a young man, Crocius studied in Herborn, Marburg, Bremen, Basle and Geneva, and through his travels began to develop a wide network of correspondents across the Protestant world. He was eventually called to Bremen to serve as professor at the city's Gymnasium illustre, an institution that has been aptly described as a ‘fortress of Reformed education’. In his first foray in the arena of theological controversy Crocius faced a formidable Catholic opponent as he engaged in a lengthy polemical battle with Galileo's interlocutor, Cardinal Robert Bellarmine. A few years after this encounter, he represented the city as a delegate at the synod of Dordt. Reflecting the desires of an urban elite eager to stay on good terms with all its Protestant neighbours, Crocius cautiously sought a middle ground in the discussions intended to resolve the Arminian controversy. He publicly criticised one of the fiercest opponents of the Remonstrants and seemed sympathetic to a number of their views. Nevertheless, when the synod drew to a close, he subscribed to its canons. Throughout his career, however, he remained suspect in the eyes of more orthodox Calvinists. Leo van Santen follows his career as it moved from Dordt to a period when he began to establish himself more solidly in Bremen. He pays special attention to the connections that he developed with other irenicists who sought to bridge divides between Protestant communities. He probes his relationships and correspondence with Alsted, Calixt, Pareus, Durie and others. He gives special attention to his friendship with the classicist Gerhard Johannes Vossius, who too was suspected of Arminian sympathies.

How does this volume fit into a broader literature and what is its more general significance? On the one hand, Bremen als Brennpunkt reformierter Irenik is the archetypal monograph of the forgotten figure. Heretofore, Crocius has eluded the scholarly nets of both the historian and the theologian. There is no biography and even Otto Scheib includes no treatment of him in his massive three-volume overview of religious dialogue during the confessional era. Listing close to two hundred libraries and archives, Leo van Santen has mined institutions from Durham, North Carolina, to Dunedin, New Zealand, to give us an extensive treatment of Crocius. At the volume's conclusion he has compiled a thorough bibliography of Crocius' own work, well more than a hundred volumes. But the text is really more than a simple intellectual portrait of a single individual from north Germany. Bremen als Brennpunkt is a fascinating study of the polycentric world of German Calvinism in the first half of the seventeenth century. While for most scholars Heidelberg traditionally stands out as the Hochburg of the Reformed movement in the German lands, van Santen has laid out a more complicated topography. Through Crocius he has developed a fascinating prosopography that connects so many figures of the Reformed world together and highlights the linkages of central European Protestantism. As with any scholarly study, there are of course areas one could highlight where an author may overstate a claim or fail to develop a theme thoroughly. Though one may expect from the title and introduction a deeper analysis of Bremen in its socio-political context, a study that would do for Bremen what Tom Brady did for Strasbourg, van Santen does not go in that direction. In similar fashion there is no extended discussion of the Thirty Years' War and how that conflict may have had an impact on Crocius' thought and his reception as Howard Hotson did for the broader world of central European irenicism in his marvellous article, ‘Irenicism in the confessional age’. Van Santen instead has focused on the intellectual and theological. Such a decision is perfectly justifiable, for he has produced a first-rate study that hopefully will encourage more scholars to venture to that north-west corner of the old empire for further exploration of its fascinating religious geography in the early modern period.