'In daytime I thought I could notice the sun following my movements; when I moved to and fro in the single-windowed room I inhabited at the time, I saw the sunlight now on the right, now on the left wall (as seen from the door) depending on my movements....When later I regularly visited the garden again I saw – if my memory does not wholly deceive me – two suns in the sky at the same time, one of which was our earthly sun, the other was said to be the Cassiopeia group of stars drawn together in a single sun...'

Daniel Paul Schreber, Memoirs of my Nervous Illness