Book excerpt: Among the proliferation of Protestant sects across England in the seventeenth century, a remarkable number began adopting demonstratively Jewish ritual practices. From circumcision to Sabbath-keeping and dietary laws, their actions led these movements were labelled by their contemporaries as Judaizers, with various motives proposed. Were these Judaizing steps an excrescence of over-exuberant biblicism? Were they a by-product of Protestant apocalyptic tendencies? Were they a response to the changing status of Jews in Europe? In Jewish Christians in Puritan England, Aidan Cottrell-Boyce shows that it was instead another aspect of Puritanism that led to this behaviour: the need to be recognised as a 'singular', positively distinctive, Godly minority. This quest for demonstrable uniqueness as a form of assurance united the Judaizing groups with other Protestant movements, while the depiction of Judaism in Christian rhetoric at the time made them a peculiarly ideal model upon which to base the marks of their salvation.