Luke 1:26–38 preserves the only canonical telling of the Annunciation, when Gabriel arrives to announce to Mary that she will become the Mother of God, and Christ becomes incarnate in her womb. For many Christians the Annunciation is an historical event faithfully recorded by the disciple Luke, an ‘educated Greek Christian believer’, directly from Mary's telling. We learn next to nothing about the setting, situation or appearance of this young woman – only that she is a virgin, betrothed. Indeed, nothing actually happens explicitly in this passage. It is exclusively speech-act, pârole, out of which centuries of exegesis has spun the mystery of the hypostatic union, the indescribable, ineffable union of God and human.

Despite the gospel's lack of detail we can instantly picture the scene because of its nearly ubiquitous representation throughout western art history over the last two millennia. Since the episode is discourse-driven, concrete iconographic imagery helps to identify it visually. While the setting may vary from chapel to bedroom to study to garden, it is almost always Gabriel flying in, Mary with her book. Thousands of manuscript illuminations, altar paintings, sculptures, relief carvings, rood screens, wall paintings, stained glass, textiles and pilgrim badges depict the Annunciation scene, pervading pre-modern art in the West. As a representative example, the altogether typical Annunciation scene of a fifteenth-century book of hours, Walters Art Museum, MS W.249, fol. 37r (Figure 1), shows Mary in her aristocratic bedroom with one hand still on her open book, the other hand raised in greeting to the angel, while Gabriel wields the banderole of his words to the Virgin which also form the Ave Maria prayer. The Holy Spirit in the form of a dove and shafts of light represent divine conception. As in many Annunciation illuminations, Mary's book contains writing that is just barely illegible: its unreadability leaves it open to interpretation and allows it to bear multiple layers of meaning. The long, rich tradition of these layers of meaning of Mary's book forms the basis for this study.

On one level Mary's reading could be the Old Testament prophecies foretelling the Incarnation, such as Isaiah 7:14, ‘ecce virgo concipiet et pariet filium’ (Behold a virgin shall conceive and bear a son) or Psalm verses interpreted allegorically to relate to the Annunciation.