Light–Shadow Interactions in Italian Medieval Churches

In the relationship between architecture and the sky, it is possible to identify three different design issues. The first regards the alignment of buildings with visible points on the horizon that coincide with the rising or setting of a celestial body (sun, planets, stars, or moon) on particular dates during the astronomical year (or liturgical year for sacred buildings). The second is the relationship between planimetric design and the design of the elevations. We are all familiar today with several “light effects”, which sometimes have almost hierophanic characteristics that, on certain days of the year, were used to engross, captivate, and amaze the spectator. Contrary to the first two issues, the third comes after the design and building stages and concerns the question of decorative elements. It is reasonable to believe that many years after the works were terminated, certain wall finishings were chosen over others, such as painted frescoes or statues. Whoever did this was fully aware, thanks to direct observation, that such decoration would be struck by a single ray of light on a specific day. This chapter examines light-shadow interactions in some Italian medieval churches.