This study analyzed the linguistic resources for organizing the content of elementary school history education texts by adopting systemic functional linguistics as an integrative approach to curriculum. Specifically, attention was drawn to the ‘이다(ida)’ construction as a relational process type within sentences, which allows for the representation of attributes or identifications of entities. The aim was to understand how sentences are structured, with a focus on how clauses containing ‘이다(ida)’ contribute to the thematic structure as key elements. Through this analysis, the study aimed to demonstrate that linguistic knowledge derived from Korean language education can be integrated with the developmental structure of other subjects’ content. Furthermore, this research serves as an attempt to elucidate the linguistic communication methods and content description techniques within subject education at a more concrete level. It may contribute to providing methodologies that content experts can utilize when describing textbooks or instructional materials. Simultaneously, from the perspective of Korean language education, it can contribute to the development of specific educational content regarding academic literacy, building upon existing research in Korean grammar education related to academic literacies.