From the beginning of the seventeenth century, Englishmen professed as Benedictine monks in mainland Europe began returning to their homeland. Until that point, the Catholic mission to England had been run by secular clergy and Jesuits, relationships between the two clerical parties growing increasingly troubled over how the Catholic Reformation should be implemented in England. The arrival of the Benedictines saw the offering of a “third way” to England's proscribed Catholics. Yet with the various missions dependent on lay Catholic resources and support both in England and in mainland Europe, it was necessary for the Benedictines to justify their presence in this often fraught environment. As such, they forcefully laid claim to contemporary English Benedictine martyrs against rival claims by other clerical groups. These battles for validation reached a new level of intensity following James I's serving of the Oath of Allegiance. This article explores how competing groups of English missionary clergy sought to justify their presence in England. Taking the case of two conflicting images of the executed George Gervase, it argues that the contest for martyrs sheds new light on the ways in which martyrdom was exploited by different groups; it also contributes to debates about the Oath of Allegiance, which was threatening to derail the wider Catholic Reformation across mainland Europe. By placing these clashes over English religious identity in both domestic and international contexts, the article makes evident that events on the peripheries of mainland Europe affected discussions at its center.