The Annunciation is described in the Gospel of Saint Luke: the Archangel Gabriel appeared to the Virgin Mary, hailing her and telling her that she would conceive a son through the intervention of the Holy Spirit (sometimes shown in paintings as a dove descending along a stream of light). The Child should be called Jesus, who would be the Son of the Most High (Luke 1: 26-36).
Usually only the archangel and the Virgin Mary are shown, but sometimes other figures are included, as in Crivelli's 'Annunciation' in the Collection, which was commissioned to celebrate a particular 15th-century event.
The feast day of the Annunciation is 25 March.