Abstract.  European constitutional traditions share a commitment to freedom of conscience and religion, but differ on their interpretation of whether such freedoms do or do not require a clear cut separation of state and church. Weiler has advocated that the writing of a Constitution for the European Union is a very apt moment to reconsider the conceptualization of freedom of conscience and religion. On constitutional and historical grounds, he has advocated that a reference to Christian values should be made in the preamble of the European fundamental law, and that this will be the alternative most respectful to the pluralistic national solutions, ranging from republican non-confessionality to the establishment of an official church. But contrary to what Weiler argues, the drafting of the constitution of the European Union is not bound by the present shape of European constitutional traditions; moreover, it is hard to conclude that the present common constitutional traditions require an explicit reference to Christianity to be included in the text. Furthermore, the claim that the individual and collective identities of Europeans are unavoidably shaped by Christian values is only tenable if we uphold a rather simplistic relation between history, memory, and identity. Finally, once one moves from law and history to practical reasoning, one finds that there are good substantive reasons why our collective identity should not contain reference to Christian values.