Despite the great achievements for peace and economic prosperity, the European project has recently been challenged with public support being on decline in many member states. If national identity remains strong and if, additionally, some kind of European identity is missing, a divergence between economic interests as has been shown during the recent sovereign debt crisis is putting at risk the future of the EU (Alesina et al., 2017). Against this background, this research project investigates how European identity among EU citizen could be initiated and encouraged. Based on a survey of various definitions of European identity and their respective measurement as well as of empirical studies, this project seeks to evaluate current trends in the development of European identity and to yield insights into their causes. Building on this, we develop proposals on how to foster European identity. Accounting for the particular experiences in the member states, we identify measures that are promising to raise the feeling of belonging to the EU. In light of seemingly increasing centrifugal forces, these measures shall revive the spirit of "united in diversity".