The Orthodox theological tradition is constituted mainly by Greek theology and Russian theology, among which a certain relationship of inheritance exists. The Early Fathers had many theoretical advances in theology; the Medieval Fathers concentrated on spiritual practices; and the Later Fathers combined and developed the theology and spiritual practices of the earlier ages. The anthropological problem in Greek theology is highly appreciated in Russian theology. Vladimir Lossky, a renowned Russian theologian, established his conception of individuality on the basis of the Patristic tradition, regarding the individuality of man as imago Dei in man. For man, individuality is the most fundamental, and it pertains to the entirety of the essence. While the Original Sin has corrupted the essence of humanity, it has not destroyed the individuality of man. While the saving act of Christ points to the essence of man, the acts of the Holy Spirit point to the individuality of man. With the notion of the individuality of man, Lossky interpreted the Orthodox conception of deification as the union of human as individual and God as individual in the uncreated energies. Lossky's conception of individuality is the inheritance and development of the Patristic theological tradition.