In the work of Konstantin Philosopher (Konstantin Kostenecki) named Skazanije o pismeneh appears the word vytrenica. This word is related to the word vetar („wind“) which is, according to the myths of Slavic peoples, inhabeted by the souls of dead people and demons. Evil winds are the source of many hard diseases such as epilepsy, mental derangement, rabies. vytrenica is a witch, a demon which predicts some unfortunate events. It appeared in Belgrade after the death of Despot Stefan, announcing to its citizens the fall of the town and misfortune. Fortunately, predictions did not come true.