Among the countless representations of the Annunciation scene, we have identified 25 which include an hourglass or a clock. This apparently incongruous detail, which has escaped the attention of many exegetes, is the subject of an iconographic analysis based both on the history of theology and the measurement of time. The analysis of this theme is also an opportunity to revisit methodological questions. We propose that the sermons of Saint Bernardino of Siena had an influence on these representations of the Annunciation scene. The corpus extends from the middle of the fifteenth century to the beginning of the seventeenth century and covers the territory from Tuscany to the Netherlands and from France to the Germanic countries.