Latin in Byzantium is a project on the linguistic competence, the cultural identity, and the transmission of the Latin texts in the "noua Roma", between the fourth and the ninth centuries. The study of different fields (law, grammar, religion, tactics, etc.) and of a multiplicity of forms of writing (palaeographic, epigraphic, and papyrological ones) will give, for the first time, an in depth knowledge of the Latin speaking milieus in Byzantium and of the contexts where Latin was used. Taking into account the political and sociological factors will permit us to put the ancient sources in a broader problematic, across multiple disciplines and beyond the gaps between literary and non-literary texts, history and philology.