"In his advice book for married women, the learned knight, diplomat, and royal advisor Philippe de Mézières (1327–1405) links the image of the clock with the exemplary figure of the Virgin Mary. As conveyed in Le livre de la vertu du sacrement de mariage (1389), the clock’s wheel represents nature at work in Mary’s body, turning at a measured pace only through her unique chastity and sobriety; the escapement, moving to and fro, is likened to her mediation between Christ and humanity, by which she restrains the weight of divine justice (Mézières 1389, 170–171)."
The confinement of the medieval European imagination to such a narrow range of metaphors is why I also find the paintings of the period so incredibly boring. Every single painting is Mary holding the baby Christ or one of the other 2 or 3 approved things to paint, all of Jesus. What a stultifying time that must have been. Although peasant culture / working class culture was probably more colorful and varied, but unfortunately illiterate and seldom recorded.
I love that, though! The same approved theme and pose, say the annunciation, painted by so many people over so many centuries lets you compare styles and trace their evolution much more directly than if they were painting random stuff. It's like watching different martial artists executing the same kata.