“L’art des architectes et des maçons et celui des sculpteurs et des peintres sont intimement liés : il y a parfait accord entre le mur, le décor et la fonction des deux. L’ornementation souligne les articulations et met en avant la capacité des architectes à construire des murs et des voûtes en pierre.” (http://www.alienor.org/articles/elements_roman/texte.htm)
What does it mean to study “the arts”? How do we classify art? What is art? The word originally comes from Latin ars for “skill, craft” and is first attested in 13th-century French as “skill as a result of learning or practice.” (http://www.etymonline.com/index.php?term=art)
In the 5th century, Martianus Capella defined the seven liberal arts as: grammar, dialectic, rhetoric, geometry, arithmetic, astronomy, and music. These were then adopted by the medieval cathedral schools into the Trivium (grammar, logic, rhetoric) and Quadrivium (geometry, arithmetic, astronomy, and music). Alcuin, having received this training at York in the 8th century, went on to further expand the arts at the Frankish court of Charlemange in founding the palatial school, which would later develop into the medieval university of the Renaissance of the 12th Century.
But where are the art classes on architecture? on sculpture? on painting? For medieval craftsmen, these were skills not learned in the classroom, but acquired through apprenticeship. Knowledge as techne (craft) must be distinguished from knowledge as philosophia (theory), which was the focus of the medieval education—learning not just how to live, but why.
Yet, philosophia was not wholly divorced from techne in medieval art, especially in the construction of cathedrals. Intuitively, one can assume that the skill in masonry and architecture displayed in Romanesque art certainly required a knowledge of arithmetic and geometry. How thick should the walls be to support a roof so wide and so high? How many windows and how big can be put into the walls without compromising the integrity of the building? What type of stone is being used and what are its properties? These and many more questions had to be taken into consideration in order to build a Romanesque cathedral that would last not just ten years, or a hundred years, but for thousands of years into the future.
And moreover, the knowledge of music and astronomy were also essential to the construction of Romanesque churches (though the techniques were further perfected well into the Gothic age). Consider music; arches and vaults were so built that the stone harmonized acoustically with the choral hymns. Or take astronomy; windows were built in such precise positions relative to the motion of the rotation of the earth around the sun, that on one particular day of the year (often the feast day of the saint for whom the church is named) at the exact time when the priest would offer the Eucharist, the window would allow the sun’s rays to fall perfectly above the altar, illumining the Host with holy aura.