The most numerous Orthodox people organized nowadays administratively within the Russian Orthodox Church knew its beginning in the efforts of a Christian woman who remained over the ages as the enlightener of the Russian people – Olga, commemorated as a Saint in the Orthodox calendar on July the 11th was as it is mentioned by an important historical document – a descendant of a ruling family with Varangian Russian origin. Wife of prince Igor, the son of the prince from Novgorod, Olga was involved in the administrative affairs of the state from Dnipro. In this quality she met the delegation of the Byzantine Empire with which she settled commercial relationships around 903. This is how historians explain the fact that after the death of her husband, Olga allowed the Byzantine missionaries to come in the cities of Kievan Russia and make known to the people the Gospel of the Saviour, Jesus Christ
The light of Resurrection and the Grace of the Holy Spirit penetrated the heart of empress Olga. The documents of that time testify that Saint Olga was invited at Constantinople where she saw the harmony between music, icon and liturgy in the great cathedral from Hagia Sophia.
It is not known precisely how long she stayed in the capital of the Empire but the Kievan chronicle show that Olga received the Sacrament of the Holy Baptism in the year 957 and the name of the Holy Empress Helena
Returned to her homeland she began to preach the right faith among her people, she built churches among these being the holy cathedral Saint Sophia from Kiev where it is found a small part from the wood of the Holy Cross given by Teophilact the Patriarch to the holy empress.