This study proposes to investigate how the media culture influences the subjectivity of a seventh grade History teacher in elementary education. The classroom observation was carried out during an exhibition of the feature length movie “A Knight’s Tale” on the theme focused on, the culture of the Middle Ages. The strategy used was to monitor the development of one stage of the teacher’s teaching plan, in which both the use of video and the discussion of the cultural theme were considered, in such a way that it was possible to analyze everything, from the use of the artifact through to its mediation and repercussions on the students’ academic work. Besides observing three classes, I also interviewed the teacher twice.