In order for the proclamation of the Gospel to be effective and meaningful, a great deal depends οn methods and strategy of communication. St Photius the Great, before dispatching the two brothers Ss Cyril and Methodius to the mission field, certainly had an elaborated and concrete plan, inspired by an elasticity of local customs and tradition of the indigenous people, respecting them as persons and without hurting their sensibility. When St Methodius, tired from intrigues and hostilities from the Germanic clergy, was thinking of retiring and returning to his dear contemplative life in the Byzantine monastery, St Cyril wrote to him to persuade him "how mission, instead, was more preferable than return to the monastic life, in this particular situation." This view echoes the staunch belief of St John Chrysostom who, in many cases, finds evangelism more difficult than the work of a retired person in the desert.
All missionary activities taken by St Photius the Great are distinctive for their flexibility, freedom, and realistic applicability. Every care was taken to avoid carrying out evangelism in an imposed and irrelevant manner. The Khagan (ruler) of the Khazars threatened that those who refuse to become Christians, preferring rather Judaism or Islam "will be swiftly put to death." However, St Cyril defends free οption, the "voluntary baptism" in full conscience, without any pressure.
Pluralism in customs, traditions, and languages is seen in reference to the Apostle Paul’s instruction: "All things to all people" (Ephesians 1: 23), by using all the positive and innocent elements in the life of a people as instruments for the glory of God. The use of the principle of applicability can be seen in the instrumental language of Slavonic, carefully avoiding any foreign language, so that evangelism was not seen as a kind of cultural colonialism, as unfortunately was the case in the intensive foreign mission of European missionaries during what is known as the colonial period, in Africa and Asia as well. Such unwise tactics discredited Christianity, and the Gospel of Jesus is still identified with Western culture and background by many Africans.
The introduction of pluralism in the life of the Church is (in part) attributed to St Photius the Great. Human beings cannot everywhere live the oneness of faith in the same way. Faith is shaped according to local customs and language, and due respect is demanded. Against any uniform stereotyped pattern in worship and religious life, St Photius the Great supported liberty in expression and formulation of the faith, without altering unity: "The different expressions, do not hinder the unity of the Spirit's grace." Thus, all newly established autonomous churches were free to develop their οwn structure in unity.