Somos explores when, how and why religious justifications faded from mainstream legal, political and scientific writings in the west by concentrating on the discourse of historiography and focusing on the ‘short yet seminal period of intense localised secularising activity undertaken by the Leiden Circle’ (p. 439), a self-conscious group, including Joseph Scaliger, Daniel Heinsius, Petrus Cunaeus and Hugo Grotius, that ‘secularised in the pursuit of peace, without being atheists’ (p. 3) in early modern Holland. Somos discusses the terminological and conceptual intricacies around secularisation concisely, identifying the process as gradual, piecemeal, asynchronous and loaded with unintended consequences, though his treatment of medieval theological politics is narrow. The roots of secular historiography, he argues, are to be found in ‘the gradual realization of the far-reaching consequences of the unraveling Reformation’ (p. 39). The dawn of modernity saw ‘vigorous experimentation with possible models for re-founding historical method and fact’ (p. 41). Somos recognises Scaliger's towering contribution to philology but rates his innovative historiography and its impact on Christian theology as ‘revolutionary’ (p. 50), particularly his refusal to grant privileged epistemic status to any subject of historical inquiry, and his denial of any causal connection between antiquity and authority. Secularisation was the ‘inevitable corollary of Scaliger's historicisation’ (p. 87). Somos argues convincingly that Heinsius, although probably a more orthodox Calvinist than his fellow Leideners, sought a radical disjunction between secular history and sacred meaning and the removal of theological debates from history-writing to minimise potential areas of religious conflict. In De republica hebraeorum libri tres (1617), Somos suggests that Cunaeus, by highlighting irreversible discontinuities between the divine Hebrew theocracy and the post-captivity Jewish republic as well as the impossibility of tracing direct descent from Israel, David or the lost tribes, ‘did to Israel what Scaliger did to the Hebrew language; he put it beyond the reach of those who mixed religion with politics’ (p. 202). His Menippean anti-theology satire Sardi venales (1612) caused Leiden students to riot, professors to protest and the temporary shutdown of the university. In an intriguing analysis of De iure praedae, Somos shows how Grotius sought to demonstrate the undesirability of deploying the Bible in legal arguments due to the inherently debatable nature of biblical interpretation. His strategies included historicising conventionally accepted universal laws, selective citation, deliberately citing inapposite verses or omitting to reference any biblical sources for key arguments, and prioritising pagan sources. As Somos judiciously concludes, this did not mean that Grotius wished to undermine Scripture but that he was intent on removing the Bible from politics in general and international law in particular. By using interlinked character studies, Somos renders the subject matter more manageable but at a cost in terms of coherence. Context is often provided via lengthy digressions and a thematic approach to the work of the Leiden circle could have resulted in a more elegant argument. This detracts but little though from what is a substantial, insightful and persuasive study that deepens our understanding of pivotal but often misunderstood currents of thought that helped to shape western modernity.