Rusalje

In Polish mythology, Rusalje are the spirits that live in the waters from Fall to Spring; in some traditions they reside in the waters from Summer to Fall. In other tales, they become the Sky Women when they return from the waters. They are called Queen of Fairies and it is said only witches dared to swim with the Rusalje. The belief that the thunder and lightening of spring time was brought by the Sky Women mating with the thunder gods; so Spring festivals included celebrating the return of the Rusalje from the waters by placing wreaths on the waters, circle dances, and fire festivals. They brought moisture to field and forest.