This paper explores the issue of metalanguage and writing instruction in the senior secondary curriculum. It reports on the use of a design based research collaboration between a very experienced teacher of Ancient History and a research team with the aim of improving literacy outcomes for a group of disadvantaged students. The case highlights some of the challenges implicated in this close work between educational linguistic theorists as language specialists and classroom practitioners as subject specialists. In particular, it raises the issue of how to provide already experienced teachers with a metalanguage to express their implicit knowledge about text more effectively in the classroom. It demonstrates both the struggles involved and the positive impact of making texts more visible, and reveals the benefits of a focus on explicit teaching of writing. It also raises some implications for future in- and pre-service teacher education.