This article explores supervision conferences in (Religious Education) RE teacher education in Sweden. Two discourses that are often articulated in supervision conferences are 'representation' and 'safe space'. These are investigated and presented as necessary components for becoming a competent teacher of upper secondary school RE in Sweden. The empirical material consists of observations of six RE supervision trialogues and interviews with the participants -- student teachers, upper secondary school supervisors and university-based teacher educators. Based on the analysis of the empirical material, representation and safe space emerge as essential 'RE teacher knowledge'. Furthermore, the antagonism between representation and safe space that emerges in the supervision trialogues is explored and highlighted. By way of conclusion, the presented discursive struggle is reflected on as a battle over power within the supervision triad.