Rosettes and Revelations Pt.1: The Holy City - Koen Gheuens and Cary Rapaport

[Koen G]

Civitas Dei surrounded by the Four Rivers, that's quite spectacular. Also, an unusual choice to use the four rivers.
Do you have a date when it was made?

In the case of the Aachen mosaics, they are late copies of the original Byzantine scenes, so it is kind of tricky to figure out what was original and what they may have changed. Either way I wouldn't use this as a reference, but it is a beautiful mosaic nonetheless. I think they chose the four rivers because, following Augustine, there was often the thought of New Jerusalem "merging" with the whole world, the whole Christian community (Ecclesia) becoming the "Civitas Dei". The Latin has the advantage that "civitas" can be read as both "city" and "society". And four is the number of the world (four winds, cardinal directions...), hence also the importance of the square shape.

As you say, in manuscript art there is a lot of variation when depicting the city. There is some degree of artistic freedom and challenge. But I think an important factor is also that many illuminated manuscripts of the Apocalypse are actually commentaries, like the Beatus tradition. So the text of the commentary may influence which items they emphasize, which symbolism they add and so on.