The didactics of multilingualism is a key subject of discussion in today‘s foreign language teaching. In terms of politics, multilingualism is a primary goal of foreign language teaching in Europe at least since the White Paper on Education of the European Commission‘s European Commission from 1995. The European Union has repeatedly emphasized the commitment to multilingualism in terms of educational policy in numerous documents such as the ”new framework strategy for multilingualism“ published in 2005. The article outlines the development of didactics of multilingualism in general. Both historical dimensions and current developments in theory and practice of multilingual didactics are shown. For that purpose, the following discourse and action areas of a so-called ”aufgeklärte Mehrsprachigkeit“ are presented: productive skills and competencies, English, Latin, Greek and other foreign languages taught in school, German as a first language / German as a foreign and a second language, language of origin and family language, receptive variety competence, multilingual subject teaching and transcultural communicative competence. Moreover theories and models of multilanguage acquisition are introduced. Last but not least, empirical findings to promote multilingualism at schools in North Rhine-Westphalia brought to the fore. The ongoing research at the UDE focuses on the attitudes of trainee teachers and teachers of foreign languages in terms of multilingualism. Selected results from four individual studies are presented. These studies provide insight into current research projects being carried out directly by the ‘Institut für Romanische Sprachen und Literaturen’ (Professur für Fachdidaktik der romanischen Schulsprachen) or by the ‘Professur für Fachdidaktik der romanischen Schulfremdsprachen’ in partnership with the ‘Institut für Deutsch als Zweit- und Fremdsprache’.