One of the chief Slavic deities, often acting as a superior over other deities (similarly to Zeus or Odin, unfortunately Slavic gods are not so well known). His companion is Perperuna, usually identified with the forces of fertility. Of course, the name Perun should be associated with something, namely with a thunderbolt, because the god Perun is e.g. the lord of thunder. Paradoxically, however, his name is chronologically primary, while the name of the atmospheric phenomenon is secondary - in other words, first there was a deity called Perun, and only from his name the atmospheric phenomenon took its name. In the case of Perun, there is a rich collection of folklore materials, oral and some written records. Researchers find them in virtually the entire Slavic region, as well as in the Baltic peoples. However, this undoubted advantage may cause some problems. Aleksander Bruckner proves that Perun (at least under this name) is known only in Ruthenia. Aleksander Gieysztor completely disagrees with this approach, proving that deities identical with Perun can also be found in other Slavic-speaking areas (e.g. Perkun appearing in the beliefs of the Balts, to cite only the simplest, most obvious example). The very stem "per" (or "perk") simply means "to strike", so perun (perkun and derivatives) is simply "a person who strikes" - and lightning also strikes, hence the simple analogy to the atmospheric phenomenon. Let us leave deeper word-formation inquiries to linguists, and those who are unsatisfied in this matter are referred to the above-mentioned researchers.

Perun, as has been said, is the god of thunder and, more broadly, of the heavens and the atmosphere as such (his dualistic opposite is Weles, the lord of the underworld and the afterlife). It combines the functions of a deity exercising power over the law, as well as a military deity, associated with strength - in various historical periods, one of the functions often prevails over the other (e.g. after the 10th century, Perun was especially identified with the army, Slavic warriors referred to him) . In mythology, Perun is often shown in a struggle with Vij (a snake, dragon, or other sea monster) as a metaphor for the fight between good and evil, analogous to other mythologies (Zeus - Typhon, Marduk - Tiamat). His similarity with the Norse Thor may also not be accidental - there are assumptions that there was a certain "exchange" of beliefs between the Slavic and Norse peoples (although it is difficult to determine from whom to whom). The personification of Perun in nature is an oak (Latin querkus) and animals such as a bull, ox, ram or dove. Places struck by lightning (especially trees or stones) are considered sacred. Also, the remains of such an event acquire special properties (become apotropeions) - fragments of boulders, pointed and resembling arrowheads, are a very valuable find and can help in various situations, e.g. when a cow does not want to give milk, you should rub her udder with such a shard . In this way, Perun is also associated with the weapon of bow and arrow. One of the attributes of this deity is the ax, which thus has certain magical properties and can be used for protective purposes against disease and impure forces. The ax is placed under the bed of the woman giving birth or, for example, on the field during sowing to protect against hail. There is also the custom of hitting one's head with a stone (or iron) after the first thunder of spring is heard.