The fundamental law of the Church (Lex ecclesiae fundamentalis) would have been an opportunity to translate the ecumenical and interreligious impulses initiated by the Second Vatican Council into canon law. The Council renewed the Catholic Church's attitude towards other Christian churches and non-Christian religions by using the model of concentric circles in both Lumen gentium and Nostra aetate. The Catholic Church does not appear as separate from the others anymore, but, while remaining at the centre, maintains a relationship of varying proximity or distance. The last draft of the Lex ecclesiae fundamentalis, dating from 1980, adopted the model of concentric circles in its first article: can. 6 considered Catholics, can. 7 Christians in communio non plena, and can. 8 non-Christians and catechumens. Initially, the project to draft a fundamental law for the Church attracted considerable ecumenical attention. The 'Working Group of Protestant and Catholic Canon Lawyers and Theologians' in Heidelberg even drafted its own version in 1971. However, distorted ecumenical assumptions ultimately contributed to the project's demise. On the one hand, there was a mistaken expectation that the fundamental law should provide a basis for the whole of Christendom, but on the other hand, it was accused of usurping non-Catholic communities. In reality, it claimed validity only for the Catholic Church, but would have clarified the legal relationship with other communities. By limiting itself to a core set of norms uniform for the entire Catholic Church, the fundamental law would have marked the scope for legitimate diversity in the universal Church. The speaker points out that the draft, nevertheless, retains its importance for legal relations with other churches and religious communities.