One of the most beautiful European cathedrals is located in Cologne. The construction of the building started in 1248 but in the XVIth century the works were interrupted. In the XIXth century, the German nationalism commanded restart the works and the majestic gothic building was finished in 1880. The cathedral is spectacular and it has a beautiful mosaic on the floor in which we can admire the seven liberal arts near the altar.
In the Vth century, Martianus Minneus Felix Capella wrote a great work on the seven liberal arts. These disciplines were established as the educational system in the Middle Ages in all schools and the new created universities. These seven arts were divided in what we now would call “letters” and “sciences”: the trivium and the quadrivium, respectively. The trivium (or “three-way”) was the set of three literary disciplines: Grammar, Dialectic and Rhetoric. In turn, the quadrivium (or “four-way”) were the Mathematical Sciences, namely Arithmetic, Geometry, Astronomy and Music. The Arithmetic is the first picture of this post and She has some coins in her left hand and She’s counting with her fingers.
The Geometry is holding the Euclidean demonstration of he Pythagoras theorem: