Mentoring is one of the main tools for training novice principals, but its contributions to development of professional skills are yet unclear. To unpack the contributions of mentoring to novice principals' professionalism, we first developed a conceptual framework based on the surface, deep, and implicit structures of Shulman's signature pedagogies, and the professional skills of diagnosis, intervention, and inference, according to Abbott's theory of professions. Using these frameworks, we explored the imprints left by mentoring on novice principals. The methodology includes content analysis of semi-structured interviews conducted with 15 Israeli novice principals on their mentoring experiences. The findings reveal that novice principals experience two contradictory messages: the principal as an omnipotent hero who can survive and cope, immediately and alone, with all professional tasks, and as an obedient bureaucrat who needs empathy and care. We conclude that while their mentors helped them to fulfill their obligations, they did not contribute to the development of the principals' skills of diagnosis and inference of previous events. Theoretical and practical implications are presented in the discussion.