Shortly after World War I, Ro­mano Guardini formulated a sen­tence that soon became a stand­ard quotation in German Catholicism: "An event of incal­culable importance has begun: the Church is awakening in peo­ple's souls." The Second Vatican Council was the fruit of this awakening. It put into words and dedicated to the entire Church what had matured in the way of a knowledge born of faith in the four decades between 1920 and 1960 which were so full of be­ginning and hope. In order to understand the Second Vatican Council, we must take a look at this period and try to recognize, at least in broad strokes, the lines and currents that led to the Council. I want to begin in each case with the notions that were held during this period in order to develop from them the basic elements of conciliar doctrine in the Church.