Siuda Baba, a person appearing on the Easter Monday in only a few villages in southern Poland, is a great example of how bits of the informations about the old religions and customs were carried on by rural communities over the long centuries and how they survived in a form of local folklore traditions.
This day, also called Lany Poniedziałek (Wet Monday) or just Dyngus, is an ancient pagan tradition celebrated in Poland on the Easter Monday, nowadays intertwined with the Christian celebrations of Easter.
It has its roots in old Slavic traditions of throwing water on people in rites meaning to purify them for the arrival of spring. On that day, groups of boys (often in festive clothing) were throwing water on the girls or even soak them completely in nearby rivers and lakes. Naturally, the girls were getting their ‘revenge’ in a similar way.