The contribution addresses the popularization and iconization of an archaic writing system in the Croatian speaking area, the Glagolitic script. This alphabet, created in the 9th century in the course of Slavic missionary work, is no longer used as a system for writing but has recently undergone a reinterpretation of its semiotic basis. Despite a lack of current referential function, the Glagoljica has been conventionalized as an autochthonous national heritage, as a special sign of Croatian cultural and, thus, also national identity. After a brief overview on the script’s history, the article discusses its recent use in popular and everyday culture with a focus on fashion and then elaborates on the introduction of a specific “Glagolitic celebration day” in the Croatian society. The article conceives the Glagolitic writing system as a cultural phenomenon and icon, which, as such, has no fixed meaning, but depends on context and its incorporation into prevailing ideologies. The research is guided by considering writing as a social practice, as well as the use of writing system and its history as an instrument for legitimizing affiliations as well as for demarcation, based on strong ideologization.