We also know this:
Young Professor Ratzinger, then just 30 years old, took part in the Council from the inside, aligned with the most radical progressive theologians (the Rahners, de Lubacs, Congars, etc.), those forming the "Rhone Alliance." In his memoirs he seeks to downplay his participation in this "Sodalitium." He writes that "the theological and ecclesial drama of those years [does not] belong in these memoirs".