This article examines the circumstances surrounding the condemnation and burning for heresy of the Observant Franciscan John Forest in 1538. Forest's principal ‘heresy’ was his adherence to the papacy, making him the only Englishman to be burnt for this offence by any Tudor regime. His fate, however, can be placed in the context of an increasing willingness of Henrician apologists in the 1530s to identify papal claims as heretical, particularly over the issue of the authority of a general council, to which Henry VIII had appealed over the divorce. The papal convocation of the council of Mantua in 1536–7, and Henry's need to impugn its authority, provides the immediate context for Forest's condemnation. The article also demonstrates how the harshness of Forest's treatment was related to his avowed equivocation over the oath of supremacy, and how Forest and a number of other conservative priests and laypeople were able to employ strategies to subvert the government's attempts to bind their consciences. It concludes by suggesting a number of reasons, political and theological, why the policy pursued with Forest was not repeated.