Open AccessThe Second Vatican Council was built within a solidly constituted tradition in the Catholic Church. All councils were held within the traditional and legal parameters of the Church. The question about the condition of possibility of a renewal Council under this tradition shows relevant. The Vatican II is the result of a negotiation between renewal and preservation. Pope John XXIII personally coordinated the construction of the legitimacy of the new event, following steps which may be rescued during the preparatory stages of the great assembly. The reading of this process from sociological parameters may elucidate its plausibility within the tradition and the Church's bureaucratic organization. Pope John started ably a church renewal process, opening a new phase in the long Catholic tradition. Under his Pope condition, he knew how to seed the idea of a revamping event in the name of a divine inspiration and with the set of bishops’ participation of the Church.