A mare is a malicious entity in Germanic and Slavic folklore that walks on people's chests while they sleep, bringing on nightmares.

Ynglinga saga is a Kings' saga, originally written in Old Norse by the Icelandic poet and historian Snorri Sturluson about 1225. It is the first section of his Heimskringla. It was first translated into English and published in 1844 by Samuel Laing.