Competency frameworks based on roles definitions are currently being used extensively in health professions education internationally. One of the most successful and widely used models is the CanMEDS Roles Framework. The medical literature has raised questions about both the theoretical underpinnings and the practical application of outcomes-based frameworks, however little empirical research has yet been done examining specific roles frameworks. This study examines the historical development of an important early roles framework, the Educating Future Physicians of Ontario (EFPO) roles, which were instrumental in the development of the CanMEDS roles. Prominent discourses related to roles development are examined using critical discourse analysis methodology. Exploration of discourses that emerged in the development of this particular set of roles definitions highlights the contextual and negotiated nature of roles construction. The discourses of threat and protection prevalent in the EFPO roles development offer insight into the visual construction of a centre of medical expertise surrounded by supporting roles (such as collaborator and manager). Non-medical expert roles may perhaps play the part of 'armour' for the authority of medical expertise under threat. This research suggests that it may not be accurate to consider roles as objective ideals. Effective training models may require explicit acknowledgement of the socially negotiated and contextual nature of roles definitions.