One of the features of Russian Orthodox Christianity has been the prominence of monasteries. Soon after the conversion of Russia there was founded the monastery of the Caves in Kiev; later on, there was established by St Sergei of Radonezh the famous monastery of the Trinity (now called the Sergei-Trinity Lavra) outside Moscow. Monasticism had been a feature of Christianity since the fourth century. At the heart of monasticism is commitment to the life of prayer, and in the earliest texts onwards we find 7 discussions about how to maintain a life of continual prayer. In fourteenthcentury Byzantium there arose a controversy about the so-called hesychast monks (‘hesychast’ being derived from the Greek hesychia, quietness) about claims that, through continual prayer, there could be attained the vision of the uncreated light of the Godhead itself. Hesychast monks were important in the bringing of Christianity to the region around Moscow in the fourteenth century (the circle of St Sergei). The notion of contemplating the uncreated light of the Godhead is manifest in iconography, especially of the Transfiguration of the Lord, about this time. The hesychast monks came to be associated with a practice of inward prayer (‘prayer of the heart’) achieved by practice of the Jesus Prayer (‘Lord Jesus Christ, Son of God, have mercy on me, a sinner’): a prayer that became very popular in nineteenth-century Russia, as the famous book, The Way of the Pilgrim, bears witness.