Annunciation with St. Emidius (1486), by Carlo Crivelli (1430/35-1495)

Crivelli's painting is typically of Renaissance-era experiments with the optical illusion of linear perspective. This image was commissioned for the Church of the Annunciation in Ascoli Piceno, of which St. Emidius was patron. The patron saint is depicted kneeling beside the angel Gabriel and holds a scale model of the church; the legend at the bottom of the painting reads "Libertas Ecclesiastica," which were the first two words of a papal grant that bestowed limited powers of self-government on the city on the Feast of the Annunciation in 1482. Notice how Crivelli plays with linear perspective: a shaft of golden light bursts through the heavens and all the conventions of linear perspective to connect God with a dove, which represents the Holy Spirit. Wood, 207 x 147 cm, National Gallery, London. 

Image source: The Artchive.