John-Paul Stonard in the TLS:
In the middle of the 1420s, a Dominican friar painted an altarpiece for his convent, San Domenico in Fiesole, Florence, showing the Christian story of the Annunciation. Fra Giovanni, now known as Fra Angelico, was a professional artist who had opted for monastic life largely for the freedom it gave him to paint. The altarpiece, recently restored by the Prado Museum, Madrid, where it has resided since the nineteenth century, hangs at the centre of an exhibition at the museum showing how Angelico took this freedom and created a new type of painting.
Coming across this large painted panel today, one is immediately struck by the lightness of the colours – the pink of Gabriel’s robe and the ultramarine of Mary’s gown – and the elegance of the design. In the 1420s the Dominican friars would have been more impressed by the bold and simple shape of the altarpiece, a square panel without florid carved frame or borders, as well as the startling absence of the customary gold background, either on the surface of the painting, or as a luxurious textile tenderly held by angels.
more here.