[23.] Walpole, ibid, xii; W. H. Frere, Introduction to Hymns Ancient and Modern Historical Edition (London, 1909); Wilmart, Le Psautier de la Reine etc., 362-3; F. J. E. Raby, Christian Latin Poetry (Oxford, 1927) 38-41. See also R. E. Messenger, “Whence the Ninth Century Hymnal?,” TAPhA 69 (1938) 446-464.
[24.] Gesta Caroli, I, 10; Einhard, Vita Caroli, edited by Garrod and Mowat (Oxford, 1915), Appendix, p. xxxvii.
[25.] Heimbucher, Die Orden und Congregationen etc., vol. I, 235, 237-9; Jahrbücher der deutschen Geschichte (Berlin & Leipzig, 1866-1902), Geschichte des Ostfrankischen Reichs, vol. II, 39, 42, 46.
[26.] Alcuin, De psalmorum usu (MPL, 101), Officia per ferias MPL, 101, Epistolae 84, 94, 164, 227 (MPL, 101): Rabanus Maurus, De clericis institutés, II, 49 (MPL, 107, 362): Amalarius of Metz, De officiis divinis (continuation) in J. Mabillon, Vetera Analecta (Paris, 1723) 99; Walafrid Strabo, De ecclesiasticarum rerum exordiis etc., ch. xxv (MPL, 114, 952ff.).
[27.] H. De Boor, Die deutsche Literatur 770-1170 (München, 1949) 21.
[28.] P. Batiffol, History of the Roman Breviary (London, 1912) 143-4.
[29.] Anal. Hymn. 51.
[30.] Translation of first line, J. M. Neale.
[31.] Dom P. B. Gams, Die Kirchengeschichte von Spanien (Regensburg, 1862-1879) II, Pt. 2, 302, 326-9; Z. García Villada, Historia eclesiástica de España (Madrid, 1929-36) V, 85.
[32.] De Urbel, “Los himnos mozárabes,” Revista ecles. Silos 58 (1927) 56-61.