The original documents[6] consulted for this book have been the works of art of which it treats. In the case of old books, I have also availed myself of facsimiles, which have this advantage over originals, they may be freely handled. Most interesting among them are The Book of Kells, notes from copy of plates, with remarks by Westwood and Digby Watts; and Illuminated Books of the Middle Ages, by Humphrey Jones. The authorities on Gothic architecture, which I have accepted as final, are Viollet-le-Duc and Corroyer. I have drawn much of my material from modern technical periodicals, most useful of which have been Les Arts, Revue Archeologique, Revue des Questions Historiques and the American Historical Review. Though I have had recourse to general historians who treat of the Middle Ages,—Duruy, Gibbon, Guizot, Kitchin, Saint Martin, etc.; to guide books of accepted accuracy,—Baedeker, Guerber, Guides Joanne, and Dent’s MediÆval Town Series; to encyclopedias, English and French,—to the appended list of authorities I acknowledge especial indebtedness. Even when I have not borrowed statements from them I have been influenced by them in my interpretations of the Middle Ages:

• Blades, Wm., Books in Chains.
• Boulting, Wm., Torquato Tasso and His Times.
• Bruun, J. A., An Inquiry into the Arts of the Middle Ages.
• Bryce, James, Holy Roman Empire.
• ChÉreul, Dictionnaire des Institutions FranÇaises.
• Clerval, A., Guide Chartrain (Docteur es-Lettres, LaurÉat
• de l’AcadÉmie des Inscriptions et Belles-Lettres
• et Membre de la SociÉtÉ Nationale des Antiquaires).
• Cutts, Edward Lewes, Scenes and Characters of the Middle Ages.
• Dill, Samuel, Roman Society in the Last Century of the Western Empire.
• Fletcher (Prof. Bannister and Bannister F. Fletcher),
• History of Architecture on the Comparative Method.
• Gray, Geo. Zabriskie, The Children’s Crusade.
• Gould, Sabine Baring-, Myths of the Middle Ages.
• Hawkins, John Sidney, History of the Origin and Establishment
• of Gothic Architecture.
• Hay, John, Castilian Days.
• Hugo, Notre Dame de Paris.
• Ivo, Letters of Ivo (reprint of original documents).
• Jusserand, J. J., La Vie Nomade.
• Lacroix, Paul, Military and Religious Life in the Middle Ages.
• Lang, Andrew, Books and Bookmen.
• Lecoy-de-la Manche, Richard Albert: France under St. Louis and
• Philip le Hardi; Les Manuscripts et la Miniature;
• Le TroisiÈme SiÈcle Artistique; Suger.
• Mabillon (edited by), Life of Bishop Arnold of Le Mans.
• Maitland, Samuel Roffey, The Dark Ages.
• Mandan, Books in Manuscript.
• Matthews, Story of Architecture.
• Merlet, Eugene, Bulletin Monumental, Number 67, of 1903.
• Norton, Chas. Eliot, Church Building in the Middle Ages.
• Reber, Dr. Franz von, History of MediÆval Art.
• Reinach, Salomon, Apollo.
• Rennert, Hugo Albert, Life of Lope de Vega.
• Rowbotham, J. F., Troubadours and Courts of Love.
• Stetson, F. M., William the Conqueror.
• Ticknor, Geo., History of Spanish Literature.
• Trumble, Alfred, Sword and Scimitar.
• Vasari, Giorgio, Lives of the Painters (Blashfield’s edition).
• Wiseman, Preface to Cardinal Wiseman’s novel, Fabiola.