Duncan Forbes once warned against the ‘fallacy of premature secularisation’. For a generation now, historians of the century after the English civil wars have pressed this point. Tony Claydon is pushing at an open door in insisting upon the religious dimension of English public life. But the door does need holding open, because there has been a backlash, a claim that, by 1688, English identity had indeed become secular and nationalist. And Claydon throws the door especially wide, for he argues that English religious self-perceptions must be placed in a pan-European context. This is an invigorating book about England's engagement with the ‘Protestant international’, the ‘European community of the reformed’, in its continuing struggle against the ‘evil empire’ of popery. ‘A confessional view of Europe’, Claydon writes, ‘survived strongly in the century after the English Civil War’. He rapidly reviews a rich constellation of contemporary debates and genres, from travelogues to histories of the Reformation, from party pamphlets to theological polemics, offering illuminating exemplars of each. At each turn he gently chides historians for failing to spot the international dimension of domestic controversies. If his stress on anti-popery is familiar, the accents here are valuable, such as the political economy in Protestant analyses of the poverty of popish lands. Claydon constantly alerts us to texts the salience of which is now overlooked, such as Gilbert Burnet's Some letters concerning Switzerland (1686). He shows how frequently ecclesiastical disputes depended upon asserting concord with the whole of reformed Christendom. Churchmen insisted that Martin Bucer and Peter Martyr had been friends of England's magisterial Reformation. Dissenters protested that to require episcopal ordination was to ‘unchurch’ half of Europe. Episcopalians elaborated a ‘branch’ theory of the (non-papal) catholic Church, a European family of patriarchates. Foreign policy analysts reminded people of England's noble tradition of evangelical military intervention, signally in support of the Dutch Revolt. King William's war was ‘a war of liberation for European Protestants’, and the British Empire was born in a fit of anti-popery. Claydon adds a new dimension in discussing Christendom's confrontation with Islam. In 1683 the Ottomans reached the gates of Vienna, and in the ensuing years international brigades of Christian volunteers repulsed them on Balkan battlefields. That France covertly succoured the Turks branded her as infidel as well as popish. Yet, at the close of his account, Claydon concedes a case for secularisation during the Walpolean era: by now, French popery was a ‘superannuated bogey’. His book has space for many things, but, as he admits, there is none for international missionary efforts, nor for the philanthropic fundraising movement in support of foreign religious causes. The prose is lucid, lively and inventive; the judgements trenchant (James ii was a ‘pig-headed bigot’); the tone commonsensical. In the tricky academic terrain that is neither specialist monograph nor textbook primer, this is a rewarding and persuasive portrait of Christian England in search of ever closer union with European Christendom.