(2005) What is the semi-circle at the top of each page on Très Riches Heures du Duc de Berry (4.3.6)?

The semicircle at the top of each page shows astrological and astronomical data.

Explanation:

In Très Riches Heures du Duc de Berry, there are a number of full page images, which also include calendar images. What we might notice is that there is a semicircle at the top of each page. This semicircle shows astrological and astronomical data. It is included because stars were integrally tied to the agricultural calendar. Moreover, many medical specialists used to believe that a person's health is somehow also related to the pattern of stars of the day he/she was born.

the answer is counterpoint.

counterpoint definition: "the art or technique of playing a melody or melodies in conjunction with another, according to fixed rules."

counterpoint is present in a lot of baroque music- such as bach (notably his wtc prelude and fugues) and scarlatti, but can also be found in music by mozart, beethoven. it can even be found in music as modern as john williams!