The title of this study is: “The Radiance of Light: Comparing the Medieval Tibetan and Medieval Latin Biographies of Longchen Rabjam and Bernard of Clairvaux.” This dissertation is a comparative study of two medieval texts, Chodrak Zangpo’s Tibetan rnam thar, or biography of the Nyingmapa and Dzogchen visionary and writer Longchenpa (1308-1364), Meaningful to Behold, and Geoffrey of Auxerre’s, William of St.Thierry’s, and Arnold of Bonneval’s co-authored Latin vita, or biography of Bernard of Clairvaux (1090-1153), the Cistercian mystic and writer, The First Life. Each part of this work is composed of close readings of selections from these two works. In these close readings, I use Weberian theories of charismatic authority to structure my reflections on some of the similarities and differences between these medieval authors’ respective presentations of legitimate spiritual authority in narrative form. My primary argument, developed in different aspects in each part of this dissertation, is that while Weber’s theories are useful for understanding these accounts from a sociological perspective (though in many cases even this usefulness must be qualified) they are inadequate for understanding these accounts from a contemplative perspective. In speaking of this contemplative perspective, I include not only their first medieval audiences, but us, today and now, in so far as we are also contemplative readers. Each part focuses upon a different dimension of experience—in Part 1: “Charisma and the Practice of Virtue,” the ethical, in Part 2: “Charisma and the Dreaming Self,” the visionary or the dreaming, and lastly, in Part 3: “The Poetics of Charisma,” the aesthetic.