The first chapter of UR (on fundamental «principles») is closely bound to the conciliar ecclesiology of LG, especially with the latter’s first three chapters. Furthermore, already from within the Council and pecisely because of this, numbers 2-4 of UR should be considered as a model of interpretation of LG (chapters 1-3); an interpretation inspired by concentration (=«hierarchy of truth»), and of careful attention not to confuse dogma with its historical-cultural dressing. For this reason, the verification of the «reception» of the first chapter of UR should be translated into the verification of the reception of LG (chapter 1-3) to see if this has been coherently read and welcomed according to the criteria of UR chap. 1. The first part of this present article, therefore, deals explicity with that problem while the second broadens the horizon to see how and how much of UR and LG have been developed in the light of other conciliar texts (above all Dei Verbum and Gaudium et spes). Finally the A. tries to see if, in practical steps and historical judgments, there has been coherency in faithfulness to the principles established in UR chap. 1 (pp. 461-483).