Mura di luce, facciate di diamanti. Metafore del bianco nell’architettura del Quattrocento
Building with light: a utopian idea that in its incessant changing of meaning, techniques and functions, crosses the entire history of western architecture. Raising crystal walls - transparent, or made of gold, of gems and diamonds, in other words of light - is an inherently Christian metaphor, though by no means applied to sacred architecture only. High and mighty walls of shining precious stones defend the Celestial Jerusalem: pure white, as evoked in specific working techniques of stone walls, is thus a metaphor for strength, protection, salvation, that finds abundant use in civil architecture. Out of a variety of late Mediaeval examples, during the second half of the 15th century emerges the theme of the “diamond palace”: not a building typology or a specific model, as intended so far, but rather a wall's finishing work that can be found in a great variety of contexts with military, defensive meanings. In the earliest and most ambitious examples (Naples, Milan, Finalborgo, Ferrara), the residence of the soldier, miles christianus, becomes an ideal bastion of faith, built, like the walls of the Celestial Jerusalem, from gems and light.