The opera libretto is one of the most complex types of text to translate. Although it has been dealt with occasionally in several disciplines, including literary studies, musicology, theatrical studies and semiotics, most of the issues raised in these fields do not venture beyond the prescriptive formulation of do's and dont's. This paper adopts a systematic approach and proposes a theoretical framework for analysis. On the premise that the translation of opera depends on the specific context in which it is embedded, the author first identifies the various components and the structure of this context by drawing on the concept of the "operatic system". Considered as an integral part of this system, the translation is seen in an intricate and dynamic relationship between various factors, e.g. the institutions, the agents and the audience of the system, but also the different political, aesthetic, religious and ideological values influencing the system from without. Based on the distinction between translational norms and conventions, the gestalt of opera translation is then analysed in terms of the interdependence of the plurisemiotic text and the extratextual operatic context. The theoretical model and concepts are used to account for all the different factors relevant to translation and are applied to the history of opera translation in the German-speaking countries with the intention of explaining the diversity of translation strategies adopted at different periods.