Few now would argue with Eilish Gregory's dismissal of the claim that early modern English Catholics were hermetically sealed off from wider society. Yet she is equally correct to highlight a delay in their reintegration into mainstream historiography of the period, noting that recent work on the civil wars and sequestration largely ignores Catholics, leaving their involvement confined to decades-old local studies or scattered chapters.

In Catholics during the English Revolution, 1642–1660: Politics, Sequestration and Loyalty, Gregory seeks to kickstart the rehabilitation process, focusing on the experience of Catholic gentry across England. The book is about the politics of the English Revolution, how the state used sequestration to deal with the noncompliant, such as Catholics, and how they, in turn, related to the interregnum regimes. Gregory has consulted an impressive array of local and family collections, but the principal source of material is a deep dive into the relevant papers held at The National Archives at Kew, which is a feat not to be underestimated.

The opening two chapters provide an overview of the administrative structures relating to sequestration. Because of recusancy laws, Catholics had always been at risk of sequestration, but the threat increased as Parliament stepped up its efforts during the civil wars. Gregory shows that approaches to sequestration were fluid, with power shifting between the local and the central depending on how much zeal the relevant authorities felt was being displayed by their regional representatives or whether the funds were required to wage a war against the royalists or to pay off the debts incurred in doing so. Under the English Republic, there was a further centralizing drive as parliament sought to ensure loyalty and divert money to London. Gregory outlines how the authorities started to search for “papists in arms,” but it proved a tricky job to split royalist/political action from simple recusancy. This approach waxed and waned, with some recognition that there were different groups of Catholics, though it remains hard to understand how anyone thought a Catholic could take the Oath of Abjuration, notionally designed to sort loyal Catholics from disloyal papists, when the oath involved swearing against belief in transubstantiation, the existence of purgatory, and the merit of good works.

However, Gregory here highlights one of her main points: the ambiguity that allowed Catholics to negotiate the situation. Catholic practice may have been banned, but in a climate of public discussion about religious toleration and freedom of conscience, there was wriggle room for private belief. In the third chapter, Gregory takes up this point, noting how it featured in public print debates that Catholics sought to enter. She provides plenty of evidence that printed complaints about the sequestration process were rife, but admits there are few Catholic examples, which is perhaps an issue with these earlier chapters; there is a lot of general discussion not primarily about Catholics. Nevertheless, Gregory highlights an exception in John Austin's The Christian Moderator essays (1651–53), which denounced delays in processing sequestration hearings as deliberate persecution, and pointedly attacked the hypocrisy of a regime promoting freedom of conscience while simultaneously expecting Catholics to swear against theirs with the Oath of Abjuration. This is a theme to which Gregory returns in the final chapter, as well as the admittedly fringe activities of the Catholic Blackloist group, who were strongly influenced by the thinking of Thomas Hobbes.

In the fourth chapter, Gregory outlines how the ambiguities of the period allowed Catholics to devise strategies for their petitions to compound. For Gregory, the Catholic experience matches that of the wider population: they were not singled out for special treatment but, like others, faced delays, official corruption, and incompetence, exacerbated by the ongoing centralizing process. Admittedly, Catholics could be charged with more crimes, such as recusancy, and they could be forced to sell all their property to raise the huge amounts of money required. Yet they still found room for maneuver, whether by exploiting the fact that they might hold property in different localities, or the authorities’ difficulty in working out whether a Catholic had been actively royalist or had simply sought protection in a royalist stronghold from anti-Catholic hostility and persecution, as a number claimed.

Gregory expands upon this exploitation of legal loopholes in the fifth chapter, showing that the role of networks was vital for Catholic survival. They relied on Protestant allies, their neighbors, and class solidarity, as well as kinship circles for assistance when they entered the byzantine systems involved in the sequestration process. It is interesting to note how such an approach represents a continuity from local Catholic approaches to the more active persecution of earlier decades, particularly the latter years of Queen Elizabeth's reign.

To her credit, Gregory recognizes in the book some research paths not traveled. She is right that it would be a hugely worthwhile research topic to explore how sequestration was implemented against Catholics in the colonies. Unquestionably, the material Gregory has consulted is complex and obviously would have taken a lot of time to wade through, but it would have been interesting to see how the likes of the barons Petre of Writtle fit in with her thesis, their experience having been first investigated by Christopher Clay in one of those local publications mentioned earlier: How did the eventuality of wardship complicate Catholic efforts to stop the breakup of their estates, and, in the case of the Petres, how much of a role could even high-ranking Catholic familial networks have to play?

Overall, Gregory succeeds in explaining the intricacies of a complex financial system that was constantly shifting, convincing with her argument that as sequestration evolved, so did Catholic efforts to protect their estates. In short, English Catholics sought to negotiate the turmoil of the period, social and kinship networks playing a vital role in deciding how successful they were in their efforts. Importantly, on a wider scale, Gregory plugs the Catholic experience back into the general narrative and opens the door to future research in the area.