Early Modern Socinianism has often been treated, especially by Unitarian historians, as the taproot of modern anti-Trinitarianism. This approach to the writings of Faustus Socinus (d. 1604) and of “second-generation” Socinians like Johan Crell, Jan Volkelius, and Jonasz Schlichting follows early Protestant rhetorical usage in which Socinians were construed primarily as deniers of the divinity of Jesus. Socinianism emerges in Sarah Mortimer's study as a more complicated and full-fledged theological alternate to the Reformed Protestant tradition. In her approach, Socinianism was heavily intertwined with broader anti-predestinarian thinking in the Netherlands and England, and it also had significant political applications. In the revolutionary England of the 1640s and 1650s, its impact extended far beyond the “radical” religious writers with whom Christopher Hill and others once so strongly associated challenges to Protestant orthodoxy.

In Mortimer's telling, Socinus, his Polish circle, and his European followers saw salvation as an outcome freely chosen by rational human beings, rather than one stemming from the election of an arbitrary deity. Nature reveals little about God, according to the Socinians: no moral law is written universally in the hearts of men. The only source of religious truth is the distinctive revelation found in the New Testament. Jesus is the source of that revelation. He modeled a virtuous life of rejecting sin, discerning God's will, and responding to the needs of others through good works. Nothing in the scriptural texts, to which Socinus applied the methods of humanist historical criticism, suggests that Jesus was himself divine or co-existent with God. Further, although Jesus commanded his followers to avoid sin and to choose virtue, nothing that he taught suggests that God has any intrinsic need to punish human sin. Jesus did not, therefore, die to atone for the sins of all or to provide justification though faith. Instead, God raised him from the dead to show that those who choose, through their own efforts, to follow his commands and moral example will be rewarded with immortality.

Christian faith also has nothing to do, according to the Socinians, with the civil order. No universal religious truths derived from natural law require the magistrate's support, and God ordains no union of religion and civil society in a Christian commonwealth. Individuals must be free to exercise a natural right to make personal choices about religion. Only voluntary and rational assent to the truth of the gospel can produce believing Christians. Moreover, both because the kingdom of God and human states are entirely separate, and because of New Testament injunctions about obedience to civil authority, active resistance to the state is also impermissible for Christians.

The appeal of the Socinian emphasis upon rational human choice to the Dutch Remonstrants, who sought to reintroduce human effort into the Reformed predestinarian system, should be obvious; but neither Jacob Arminius nor any of the Remonstrant thinkers influenced by him adopted Socinian Christology. The most important of these Socinian-influenced Dutch thinkers for Mortimer's treatment of England is Hugo Grotius, whose work and irenic spirit were widely admired in England by religious thinkers with reservations about predestination. Among these was William Chillingworth, the author of The Religion of Protestants (1638), who emphasized that truth may be deduced from scripture through reason and that faith and works are complementary for attaining salvation.

Chillingworth's friend and fellow admirer of Grotius, Henry Hammond, who also sought to rehabilitate the place of good works and human agency in English Protestant soteriology, drew especially upon the distinction Socinus made between nature and the commands of Christ in developing a royalist apology in the 1640s. For him and for some other royalist intellectuals, New Testament commands to obey civil authority outweighed parliamentary and Reformed justifications of resistance based upon natural law and the right of self-defense. Hammond instead viewed obedience as a requirement for salvation established by Jesus himself. Moreover, the natural right to self-defense is necessarily surrendered when men enter civil society because its continued exercise would make government impossible. Unlike Thomas Hobbes, who made somewhat similar arguments based on natural law, Hammond maintained that Christian obedience rested upon the employment of individual reason and conscience to fulfill the distinctive ethical commands of Jesus. This approach to obedience separated royalists influenced by Socinian and Remonstrant writings from most other royalists, according to Mortimer, who developed their arguments from divine or natural law, patriarchy, tradition, and hierarchical understandings of the natural order.

The central place that Mortimer accords to Hammond, who overshadows such Unitarian icons as Paul Best and John Biddle, is strikingly original. Indeed, she minimizes any explicit borrowing from Socinus by either Best or Biddle. And, although see sees a “growing chorus” of doubt about the Trinity in England from the 1630s (149) into the 1640s, this generalization is based on only a handful of individuals, excluding Holy Spirit-oriented “non-Trinitarians,” (168) whose writings were more anti-clerical than reflective of serious engagement with Socinian texts. Yet fears about the spread of anti-Trinitarian views, which were magnified by awareness of continental writing, by the publication of an English translation of the Racovian Catechism, by new voices of the 1650s, and by the spread of other heterodox ideas clearly did play a role in the politics of the Commonwealth and the Protectorate. The task of justifying a new Reformed settlement with a broad toleration that nevertheless required acceptance of the Trinity and of justification by faith alone fell, according to Mortimer, to leading Independent divines like John Owen. For Owen, Socinianism, “the Socinian strand to Remonstrant theology,” (206) and Remonstrant thinking about salvation (derived especially from Grotius and found in Richard Baxter, among others) became an essential challenge to the Reformed establishment of the Cromwellian state. The challenge of Socinianism continued after the Restoration, as both reason and holy living gained even more purchase within the re-established Church of England.

Despite its relative brevity, this is a difficult book. Mortimer's arguments rest upon her close reading and summary of dozens of texts, some of them obscure even to the specialist. The interpretation also rests upon a generous finding of Socinian ideas in the Dutch Remonstrants. But the Remonstrant thinkers disagreed with each other about much, sometimes denied the very Socinian influence that Mortimer emphasizes, and apparently were more influenced by the moderating “second-generation” Socinians than by Socinus himself. The reception of Socinian ideas by English writers, in turn, rests upon the impact of this “Socinian strand” in Remonstrant thinking. Mortimer's arguments are nuanced and replete with many careful qualifications; and yet the “Socinian challenge” to Reformed theology in revolutionary England was clearly as much Arminian as it was Socinian. Mortimer's discussion of Socinianism, Arminianism, and “Remonstrantism” (212) as “isms,” or developing theological systems, may also overly structure the selective cherry-picking of complicated texts by dozens of creative and original writers. The result is an interpretation of Socinian influence in England that paradoxically privileges the Anglican royalist Henry Hammond, who trumpeted his orthodoxy on such matters as the Trinity, the atonement of Jesus, and original sin, all of which were denied by Socinus. Similarly, Richard Baxter, the quintessential Restoration dissenting divine, becomes a chief 1650s exemplar of the impact of Remonstrant thinking and thereby part of the “Socinian challenge” to orthodox Reformed thought.

Such paradoxical results reflect complex historical realities, and these questions cannot be resolved here. All readers of seventeenth-century English theology and history are indebted to Sarah Mortimer for a provocative study that challenges our thinking about many important Early Modern English and European theological writers.