2 The purpose of the document of five years ago was to remind people of these solemn acts of the Church and to call the attention of Christians and of all people of good will who have at heart the welfare, harmony and unity of Europe to the ever-living relevance of the eminent figures of Benedict, Cyril and Methodius, as concrete models and spiritual aids for the Christians of today, and especially for the nations of the continent of Europe, which, especially through the prayers and work of these saints, have long been consciously and originally rooted in the Church and in Christian tradition. The publication of my Apostolic Letter in 1980, which was dictated by the firm hope of a gradual overcoming in Europe and the world of everything that divides the Churches, nations and peoples, was linked to three circumstances that were the subject of my prayer and reflection. The first was the eleventh centenary of the Pontifical Letter Industriae Tuae, whereby Pope John VIII in the year 880 approved the use of the Old Slavonic language in the liturgy translated by the two holy Brothers. The second circumstance was the first centenary of the above-mentioned Encyclical Epistle Grande Munus. The third was the beginning, precisely in 1980, of the happy and promising theological dialogue between the Catholic Church and the Orthodox Churches on the Island of Patmos.
Source: Slavorum Apostoli (Vatican.va)