Establishing and implementing rules that would teach pupils to become citizens became a crucial technique for turning those spots on the map of Europe whose sovereignty had shifted after the First World War into lived social spaces. This article uses Arnold Van Gennep's notion that a shift in social status possesses a spatiality and temporality of its own, in order to analyse how principals of secondary schools negotiated transformation in the Belgian-German borderlands. It asks whether and how they were called on to offer training that would make the borderlands more cohesive with the rest of Belgium in terms of the social origins of pupils and the content of study, and examines the extent to which they were historical actors with room for their own decision-making on creating and abolishing a liminal phase, thereby leading secondary education through its rites of passage.