(Also Perenu, Perkons, Perkunas (Lithuania), Percunis (Prussia) Piorun (Poland), Perunu, Pyerun (Russia)

"The Thunderer"
"The Striker"

Perun was one of the main deities in the Baltic (i.e. Latvian, Lithuanian, Prussian) folk religion. The cult of this god in the Baltic region was widely spread in the second to fourth centuries CE with the establishment of agricultural societies in those areas. Perun was first identified in the sixth century by the Byzantine historian Procopius, who noted that the god was the supreme deity of the Sclaeveni and Antes tribes.

He was a thunder-god, and the tutelary god of the Kievan state, which was the main center of worship until the tenth century. Russian myths describe him as a dragon-slayer. Some Slavic myths detailed his rise to power over the sky-god Svarog (creator god who forged the sun) and his son Svantovit, though many records indicate that Perun was long a primary deity of at least the eastern Slavic religion. He is also given the name Dievins (a diminutive form of Dievs, the supreme deity of the Latvians and often cited as a form of Svarog), which might indicate a melding of the two deities. Often the name Dievins is given to both Dievs and Perun, but each seems to maintain an individual function, and no clear hierarchy can be pinpointed.

Functions:

1. Heavenly Smith – Perun’s role of smith can be found in a small number of folk songs. There are two ways this is depicted. In one case, the role of smith was fulfilled by a separate deity who is subservient to, or controlled by Perun (like Teliavelis). The second case has Perun himself acting as the smith of the heavens. One song tells us that "Perkons hammers in the heaven". The coals from his forge would fall to earth to become silver and gold. As a combined deity with the sky-god, Perun forged the sun and the sky.

2. Participant in the Heavenly Wedding – In the Latvian Version of the Heavenly Wedding, God’s son (Dieva Dels) or Morningstar or the Moon is to be married to the sun’s daughter (Saule), and Perun is a relative of either the bride of the groom. On his way to the wedding, Perun strikes the golden oak (the thunder god’s tree). This act was said to either expel evil spirits, thus ensuring a happy union, or, it was representational of the Latvian tradition of a new husband’s relatives cutting a cross into the doorway of the newlywed’s home.

3. Persecution of a Devil – Unlike basic Indo-European myths involving the thunder god and the devil (Velns), Perun did not fight with the demon. Rather, acting as absolute justice, he persecuted and then killed him. There is also mention given to a man killing the devil with a sword made by the heavenly smith.

4. Fertility God – This can be considered the main function of Perun. As a thunder deity, all manner of rain-related phenomenon were associated with him. Perun’s family all had roles in the coming of rain. His sons would make the thunder and cause the lightning to strike. His daughters and wife would sift the rain. Together, they brought the moisture, thus making the land fertile so crops would grow. This would have been very important to the agricultural societies which worshipped Perun. To invoke Perun’s favor or call upon him to bring the rains, worshippers would give food offerings to the god. It is considered unlikely that human sacrifices were made to Perun.
In 1610 D. Fabricius wrote: "During a drought, when there has not been rain, they worship Perkons in thick forests on hills and sacrifice to him a black calf, a black goat, and a black cock. When the animals are killed, then, according their custom, the people come together from all the vicinity, to eat and drink there together. They pay homage to Perkons by first pouring him beer, which is then brought around the fire, and at last pour it in this fire, asking Perkons to give them rain."

5. Punisher – Perun represented divine justice, and as such, chaos and sin were his enemies. He would punish evil-doers and in some cases make war with the enemies of his followers.

Appearance:
Like most thunder-gods, Perun’s main accessory was a bludgeon, axe, club or hammer. He also carried a bow that was used to shoot his fiery arrows (lightning). Perun himself was often shown as a rider with a silver head and a golden beard on horseback or in a flaming chariot. He was well armed, with a sword, an iron rod, a golden whip, a fiery club, a knife and a thunder-ball. He used his weapons to create thunder and lightning, and to kill Velns. Less often, Perun was depicted as an old man, or a tiny man.

Other Information:
The thunder-wheel (a six spoke wheel) was Perun’s signatory geometric symbol, which seemed to be representative of the chariot that the thunder-god drove through the sky. His sacred animal was the bull, though it is only assumed that these animals pulled his chariot. Black bulls, cocks, goats and bears were offered to the god at Perun’s religious festivals. His main celebration date was July 20th. His name is related to the Polish 'piorun' (thunder), although cognates of it were lost in other Slavic languages. There are, however, direct cognates in the names of the various Baltic thunder-gods.

Worshippers of Perun were still in existence until the twelfth century, when Retra fell and with changing political tides, Svantovit became the ruling Slavic god and highest solar deity. As Christianity spread, the Slavic deities vanished in name, but many elements of their worship survived. These pagan rites became an important part of the Christian Slavs' religious traditions.

Sources:
http://www.geocities.com/cas111jd/slavs/slavs_perun.htm
http://www.pantheon.org/articles/p/perkons.html
http://www.geocities.com/cas111jd/slavs/slavs_svarog.htm