A common idea in The Middle Ages, was that if One felt tired or lazy during the day's work especially if One were to stop for Prayers, they were under ''assault'' by what was known as The ''Noon Day Demon''. These were invisible Demons tasked with making One tired and sleepy. Perhaps a quick nap behind the haystack Not a good idea, for that ''Medieval Power Nap'' would allow The Demon to put you into a ''deep sleep''. The end result, never finishing your work (or going to Prayer). A goodnight sleep, or Prayers in the morning were seen as some means to stop The Noon Day Demons from attacking One.