The Commission on European Family Law (CEFL) initiated a research project based on transnational collaboration that was generally believed to be impossible to realize in Europe. Never before in legal history, has such a large group of scholars investigated the possibilities for and contributed to the harmonization of substantive family law in Europe. The harmonization of family law will provide an adequate legal basis for the further realization of free movement for Europeans and will greatly contribute to the factual achievement of a Europe without legal borders. In focusing on this fundamental European right the CEFL covers the most important family law problems of today. The CEFL’s Principles of European Family Law have led to a significant increase of European competitiveness in the field of family and comparative law. The international ‘market’ of legal models, which is traditionally dominated by the American Restatements has been complemented with a European ‘product’. The Principles of European Family Law contribute to the coming into existence of a factual European family law.