Friedrich Nietzsche
Nietzsche wrote in a very fiery and exciting way. However, what he wrote later in his life became more and more odd. When he was forty years old, Nietzsche went insane. Supposedly, one day in the city of Turin, Italy, he saw a horse being whipped by its owner and ran to save it, hugging it around the throat. After this, Nietzsche never wrote again and could not look after himself. This illness may have been caused by the disease syphillis, or a brain tumour.