Mermaids in the 19th century peasant Russia were understood as drowned women or children who died before christening. They were believed to have been offended, not having lived the term granted to them by god. Therefore, they could be evil-doers, but on occasion some help could be coaxed from them as well since these characters were recently diseased relatives or neighbours. They were believed to have power over weather (calling forth the rain) and were linked to the oak, the Perun's tree. In the custom of «sending off (or driving) the rusalka away» human sacrifices were reflected: a witch or some other woman was sent to the god as an advocate for her home-folks.Some other characters were sent off too: in the early spring (on Shrovetide, in Russian «Maslenitsa») Maslenitsa was sent; in the Midsummer (on the summer solstice, or St. John the Baptist's day, in Russian Ivan Krestitel's day, or its eve, Kupalo) Ivan Kupalo was thrown into the river; among the Southern Slavs, Mara, or Marena, was seen off. As observed by Vladimir Propp, the similarity of the major components of the ritual pertaining to different festivals is striking. However, his contention that it may be explained by the similarity of peasant working operations is suspect: indeed, the seasons of the festivals are quite different.
Most likely the unity of the ritual components should be explained by homology — by common origin. The custom of erecting a fire-wheel oil a pole and then rolling it down may be connected to the magical granting of the sun descending from the highest point on the ecliptic, that is, to the St. John the Baptist's day, rather than to the spring sun still rising to the high point. Yet in fact, in Russia this ritual is seen in the Shrovetide, in the spring. However, the St. John the Baptist's feast preserved in the Ukraine and Belorussia, had disappeared in Russia proper where it was ousted by the Christian fast. Before the fast, Russia has the Shrovetide festival «Maslenitsa» that is absent in Ukraine and Belorussia. So, the ritual with its concomitant features had moved from St John the Baptist's day to the early spring where it makes the Russian Shrovetide, «Maslenitsa».
In addition to the above ritual, the Kupalo festival is characterized by elements of the Perun worship and intense sexuality. The term «Kupalo» is not a proper personal name but a kind of sobriquet, designating the main action. It is derived not from the word «kupati» («to bathe») but is cognate to the words «кира» ('pile'), «sovokuplenie» («coitus»).