Masters of gothic stonemasons had great knowledge of theology, natural sciences like also the crossover of philosophy, physics, geometry, anatomy and ophathalmology, which was central to visual experience providing a historical framework within the relationship between perception and imagination. The materiality of light was emphasized, in particular with concepts of species transmitted by ray blending models of Platonic extromission and Aristotelian intromission, which appealed to the spectator’s visual and tactile senses in the narratives of image.

This presentation focuses on sculpture as major medium in the 13th-century Germany, in paticular, works created by workshops of Cathedrals in Bamberg, Meissen and Naumburg, which I argue to be created in the novel way of combining optical theories with art, one of whose benefactors was the Holy Roman Emperor Frederick II. Preceding Robert Grosseteste and Roger Bacon, Frederick’s court was the contemporary center of discovery and translation of Greek and Arabic optical treatises, like those of Alhacen and Averroes. Frederick's great interest on harmonizing art with science is also evident in his courtly literature with detailed reference of optical discourses.

Mastermasons could combine art with science directly in practice by reflecting them on their own imagination. As both architects and sculptors, they tried to create total entity of sacred space and as their works were of central religious practices, their images had to be appealing vehicle of contemplation. The emotional effects of startling eye, orienting eyesight of direct eye contact were reinforced by epistemological optical process, which was also legitimated by theologians.

At issue are the ways in which artists responded to contemporary optical theories in creating sacred images within theological arguments, like in the interpretation of intact penetration of light on the surface of transparent objects, which thought to exemplify contemporary theological arguments about immaculate conception of the Virgin Mary. The possibilities of illustration of scientific optical diagrams directly projected on statues to represent the Virgin‘s miracle will also be pointed out.

This presentation aims to shed light on the place of scientific knowledge in artist’s practice in the Middle Ages by demonstrating one property of gothic sculpted works with dynamic combination of optical theories by mastermason imitating god as scientist as pictured in the Bible moralisée.