A Swiss artist, Henry Fuseli (7 February 1741 – 17 April 1825) is the person who introduced a female horse, a mare, into the description of a bad dream which is called a “nightmare”. We don’t know why Fuseli introduced this horse into his painting called “The Nightmare” (1781) – see below:
It’s a rather convoluted story because it is not readily apparent why we call a bad dream a “nightmare”. What has it got to do with a female horse? The reason is that the word “mare” became tangled up between two meanings. Going back into the evolution and history of the English language, the word “mare” comes from the Anglo-Saxon and means evil spirit or incubus. The evil spirit in the painting that you see on this page, sitting on the dreaming woman, causes a bad dream. In the background is the female horse and the female horse is described as a “mare”.
We don’t know why Henry Fuseli introduced the horse into this painting. Perhaps he was playing with words because as mentioned above the word “mare” means a demon and also a female horse. But in doing this the artist created a new word which is enmeshed with a horse when it shouldn’t be because it is based upon a demon causing uncomfortable thoughts in the form of a dream.
So this is a misleading association between a bad dream and a horse just to be completely clear! It appears that people have associated this demon with a demon-lover resulting in a baby who is sadly deformed and discarded. Thus there is a sexual nature to nightmares. Dr Desmond Morris tells us that in 1621 Robert Burton wrote, “Maids and widows were particularly subject to terrible dreams of the night, a symptom of melancholy which can be cured by marriage.”
In 1802, Fuseli painted a German version of his Nightmare calling it “Nachtmerrie“. The German language has the same construction of the word to describe a bad dream.