This Latin translation was used in all the Middle Ages and had many Scholastic commentators. For us he has all the main characteristics of the Byzantine end of the Greek development. He is the mediator of Neoplatonism and Christianity, the father of most of Christian mysticism. Therefore we must deal with him very carefully. His concepts underlie most Christian mysticism in the East as well as in the West, and some of his concepts – such as hierarchy, which he invented – entered the ordinary language and helped greatly to form the Western hierarchical system of Rome.