Modern Hagiography
Lives of the Saints by Sabine Baring-Gould.
Medieval Hagiography
Epitaphium Hildegardis reginae
Royal Frankish Annals – 780, 781, 783
Einhard, Life of Charlemagne
Art & Architecture
Warburg Institute Iconographic Database
The Saints in Art by Joseph Maria von Radowitz.
Nihil sub sole novum 