In England and other parts of medieval Europe, such goblins were known as mares: demons from folklore that were said to sit on people’s chests at night, causing a terrible, suffocating feeling and bad dreams.
“Mare” itself can be traced back to the Old English “mera,” the Proto-Germanic “maron,” and—ultimately—the Proto-Indo-European root “mer,” meaning “to harm” or “to die.” From this ancient root also derive the Czech word “mura,” the Polish “zmora,” and the Irish “mór,” to name just three examples.
This root is also the source of the German “Mahr” and the Old Norse “mara.” These both translate to “incubus”—a word that describes a male demon and derives from the Latin “incubare,” which means “to lie upon.” The imp in Fuseli’s painting is typically referred to as an incubus.
The other meaning of “mare”—an adult female horse, zebra, or other equine species—likewise stretches back to the distant past: to the Proto-Germanic “marhijo” (the source of the Old Saxon “meriha,” the Old Norse “merr,” and the Dutch-Frisian “merrie”) and, beyond that, to the Proto-Indo-European “márkos.”
