Pope John XXIII not only announced, but also prepared and inaugurated the Second Vatican Council. Summoning Vaticanum II was announced by John XXIII on 25th of January 1959. Few months after the announcement, the Pope set up (17.05.1959) the Ante-preparatory Commission. Commission’s tasks was to establish contacts with the Catholic Episcopates of different countries, the Dicasteries of the Roman Curia and the Catholic Universities, in order to consult and receive some suggestions regarding the Council. The head of the Ante-preparatory Commission was card. D. Tardini, then the Secretary of State. Mons. P. Felici, the auditor of the Roman Rota was a secretary. Gathering the materials took the Ante-preparatory Commission one year. On 5. June 1960, Pope John XXIII established ten Preparatory Commissions and two secretariats. The basic objectives of these organs was to study the Council’s topics indicated by the Pope. The results of these activities were published. Only the works of the Central Preparatory Commission, which sometimes included up to 150 members and contained the presidents of the other Preparatory Commissions and the secretariats were fully reconstructed. The works of the Commissions and secretariats preparing substantial issues of The Second Vatican Council are published in 76 schemas (texts). During the pontificate of John XXIII the first session of The Second Vatican Council took place (11. October to 8. December 1962). A special consideration should be given to Council’s discussion on the schema of the sources of the Revelation. After many days of a vigorous discussion there was a vote. Almost 2/3 of the participants voted against the continuation of discussing this text. However, it was not the required majority. In this situation, John XXIII personally decided to remove this schema form the agenda and established a special, mixed commission, composed of the representatives of the opposed fractions. The aim of this commission was to develop a new schema in this issue. It allowed the council to avoid the impasse. The most discussed schemas were on liturgy and on the means of social communication. The last schema was decided by vote, but only “in its essence”. The discussion on the schema on the Church, closing the first session, turned out to be the most important. It indicated the Council to present the Church in its nature, its mission and various relations with the world. The Adagia of John XXIII, which was a quintessence of the Council’s program is enclosed in a word aggiornamento (it.) or accomodata renovatio (lat.). Pope John XXIII gave his life for the Council. The author of this paper encloses a speech of the Pope John XXIII to the polish bishops, granted on 8th October 1962.