The Summa de Officio Inquisitorii of 1270, warns of the evils of all reflective surfaces: lacquer, glass, jewels, swords, water. It advises readers to avoid anything which might catch their reflection. It's more than a warning against vanity - it's a distrust of the mirror-world. The devil, or something analogous to that, controls the kingdom of reflections.
17th century thinkers are equally disturbed by the doubling -or tripling- of their own image, A French orator named Jean-Benigne Bossuet asks in a sermon, whether in anguish or curiosity it isn't clear:
"What is this image of myself that I see more deliberately still, this lively apparition in this running water? It disappears when the water is disturbed. What have I lost?"
Mirrors existed in antiquity. The Ancient Greeks and the Romans prized them though they were a poor relation to what we know now - nowhere near as big and clear. They were handheld, darker, with a dimmer reflection. Their reflections really were like ghosts, fainter than ours, more a part of the texture of the reflecting surface. Emperor Nero, so they say, had a mirror made of emeralds.
After the hall of mirrors in Versailles, something changes. Mirrors become commonplace and our own reflections stop being astonishing. Because now everybody has mirrors and cameras and film. No one is aware of the symmetry anymore, the dividing line between them and it. Other than the smallest children, we've mistaken our reflections for a part of ourselves.