This article addresses a neglected facet of a familiar political debate, the contribution of Anglican royalist writers to the Engagement controversy. A new interpretation of the core issues at stake in the debate is offered by focusing on these Anglican responses. The work of Quentin Skinner, Margaret Judson, and John Wallace concentrated on the discussion of the duty of obedience to de facto powers. This article contends, however, that it was a debate over the nature of oaths and the lawfulness of taking apparently contradictory sworn promises which was at the heart of the controversy. Writers offered competing interpretations of the bond of oaths and covenants, the supporters of the Rump claiming that they were conditional and dependent for the obligation on circumstantial considerations, the Engagement's opponents claiming that these sworn bonds were non-reciprocal and indissoluble. In this debate both pro- and anti-Engagement authors used casuistic arguments to urge their readers either to take or to refuse the declaration of loyalty to the Commonwealth. Yet, whilst in print Anglicans had counselled against subscribing, in two manuscript cases of conscience they allowed correspondents to take the Engagement.