The letter of the Holy Father John Paul II written in Rome in 1987, in the tenth year of His pontificate, on December 4th, on the day of memorial of Saint John Damascene, the doctor of the Church, on the Twelfth Centenary of finishing the controversy over the icon, is of great importance for the Pope’s program of ecumenism. The Holy Father indicated various directions of the dialogue, however, the one of the utmost importance concerned the agreement with the Orthodox Church, which was confirmed in the letters and in His other documents quoted in this paper. The image used to be essential for religious practice, for illustrating the word of prayer and of the song, in order to preserve the tradition of the Church. The strict prohibition introduced by the iconoclasm depreciated not only the artistic tradition of paintings but also the basic dogmas of Christ’s Incarnation and the one which introduced Virgin Mary as the Theotokos (the God-bearer). The ban constituted a threat not only for the icons but also for the Christian faith. In His Letter, the Pope underlined the important role of the Second Council of Nicaea which reintroduced icons and maintained and deepened the meaning of the cult in the faith of believers. Furthermore, the Holy Father indicated the connection with the Second Vatican Council in understanding the function and form of images in contemporary Church. Contemporary trends are overwhelmed by the impotence of the spiritual expression of sacral art, which is a great concern for the Pope. The Letter is, therefore, a dramatic warning of the threats for religious art in contemporary time, expressed by the Holy Father with these words: ‘The rediscovery of the Christian icon will also help in raising the awareness of the urgency of reacting against the depersonalizing and at times degrading effects of the many images that condition our lives in advertisements and the media.’ (DS, 11).