Fifty years after the Treaties of Rome were signed and especially in view of the failed constitutional referendum in France and the Netherlands on 29 May and 1 June 2005 respectively, in which the citizens of two founding countries of the ambitious Treaty rejected a unified European constitution, the question arises: what is the point of European unification? This fundamental European constitutional law question is also of great importance for the further development of European private law. Against this backdrop, this work examines the concretization competence and concretization methods in European private law.