Vienna today is an intersection of international early medieval research, where source-led approaches to identities and the formation of ethnic groups, the transformation of the Roman world, and central Europe in the Carolingian period are pursued. Herwig Wolfram is to be thanked especially for the establishment of this research direction, who as Professor for Medieval History and the Historical Auxiliary Sciences at the University of Vienna developed new approaches in the treatment of these subjects and pioneered new routes in early medieval studies. The contributions in this volume revolve around issues which, following Herwig Wolfram, have stood at the centre of the interests of early medieval research in Vienna, and have been received and further developed at an international scale. These horizons have frequently been widened: from ethnogenesis to identity research, from Carolingian Salzburg and Bavaria to a broadening investigation of the Carolingian period and its transformation, or from diplomatics to a wider social history embedded in documentary research. In this volume, contributors from the Viennese early medieval research community together with distinguished guests reflect over the current state of research and future directions. In so doing, neighbouring disciplines such as Philology, Archaeology and Art History become incorporated and emphasise the dynamics of interdisciplinary early medieval studies. Altogether, this volume offers an overview of the central questions of the foundations of medieval Europe between 400 and 1000, which are addressed here especially within the framework of a transboundary history of Central Europe.