Friedrich's Mental Illness

I read some disappointing news about Caspar David Friedrich (see last post) in the library at lunch time. Apparently he became pretty ill, and was given to fits of rage etc. To me this completely goes against what I see in his painting-- calmness, peace, evenness. Maybe it is slightly encouraging, in a strange way-- that you don't need to be a 'tranquil sea' to create something lovely and peaceful.