English summary: On January 17th, 2001, the Congregation for the Doctrine of the Faith of the Catholic Church recognised the liturgy of the Apostles Addai and Mari of the Assyrian Church of the East without the Words of Institution as a valid celebration of the Eucharist. This was a theological sensation, and in theological, pastoral and ecumenical terms seemed to be a breakthrough. Nevertheless, it sparked a heated debate, as it affected the innermost essence of Catholic sacramental theology - the question of the Words of Institution as the sacramental form of the Eucharist. The...