Contrary to other gods of the Proto-Indo-European pantheon the likes of Dyēus or Hausōs, clear cognates stemming from the root Perkwunos are only found in Western Indo-European traditions; the reconstruction is therefore less secured.
The term *Perkwunos likely stems from the verbal root *per-, "to strike". Another proposed etymology is the root *pérkʷus, the oak, attached to the divine nomenclature *-nos, "master of", with cognates in Lat. quercus ("oak-tree"), in Ger. *ferhwa ("oak"), and in Grk Herkyna (a spring-nymph associated with the Herkyna River).
His name thus either meant "the Striker" or "the Lord of Oaks". An etymology uniting those two propositions has been suggested in the mythological association of oaks with thunder, explained by the frequency with which such tall trees are struck by lightning, although this is not universally agreed upon.
Other cognates related to thunder, through another root *(s)tenh₂, are found in Germanic Thor, Celtic Taranis and Latin (Jupiter) Tonans. According to Jackson, "they may have arisen as the result of fossilisation of an original epithet or epiclesis", as the Vedic Parjanya is also called stanayitnú- ("Thunderer").
George E. Dunkel regarded Perkwunos as an original epithet of Dyēus, the Sky-God. It has also been postulated that Perkwunos was referred to as *Diwós Putlós ("son of Dyēus"), although this is based on the Vedic poetic tradition alone.
Perkwunos is depicted as holding a weapon, generally conceived as a club, mace, or hammer, made of stone or metal. In the Latvian poetic expression Pērkōns met savu milnu ("Pērkōn throws his mace"), the mace milna is cognate with mjollnir, the hammer thrown by the Nordic thunder god Thor, but also with the word "lightning" in OPrus. mealde and OCS *mlъni. His thunder and lightning had a destructive but also a regenerative connotation, as they can be accompanied with fructifying rain. Parjanya is depicted as rain god in the Vedas, Latvian prayers included a call for Pērkōns to bring rain in time of drought, and the Balkan Slavs worshipped Perun alongside his female counterpart *Perperuna in prayers for vital rains portraying the female as a virgin who had not yet had her first monthly period. The earth is likewise referred to as "menstruating" in a Vedic hymn to Parjanya, a possible cognate.
Oak-God and StrikerEdit
The association of Perkwunos with the oak is found in various formulaic expressions: Lith. Perkūno ąžuolas (Perkūnas's oak), Latv. Pērkōna uōzuōls ("Pērkōn's oak"), or ORus. Perunovŭ dubŭ ("Perun's oak"). The Slavic thunder-god Perūn is said to frequently strike oaks to put fire within them. In Germanic mythology, Thor likewise strikes his foes the giants when they hide under an oak; although he is a thematic echo and not a cognate of Perkwunos. The striking of devils, demons or evildoers by Perkwunos is a motif also encountered in the myths surrounding Perkūnas and the Vedic Parjanya.
A multi-headed water-serpent is connected in particular with Perkwunos in an epic battle: the serpent is often described as a "blocker of waters", and his heads eventually smashed by the thunder-god to release torrents of water that had previously been pent up. The myth has numerous reflexes in mythical stories of battles between a serpent and a god. The latter is not necessary etymologically related to Perkwunos, but is always associated with thunder or drought: the Vedic Vṛtra (the personification of drought) and Indra, the Iranian Tištry/Sirius and Apaoša (a demon of drought), the Albanian Kulshedra (an amphibious serpent who causes streams to dry up) and Drangue, the Greek Typhoeus and Zeus, or the Germanic Miðgarð and Thor.
He is often portrayed in connection with stone and (wooden) mountains, probably because the mountainous forests were his realm. A cognate keening appears in Ger. *fergunja ("[mountainous] forest") and Gaul. ercunia ("[oaks] forests"). Words from a root *pér-ur are also attested in Hitt. pēru ("rock, cliff, boulder"), Aves. pauruuatā ("mountains"), and Skt párvata ("rocky, cliff, mountain"). In Germanic mythology, Fjörgynn's name was used as a poetic synonym for "land" or "the earth", and she could have been the mistress of the wooded mountains, the personification of what appears in Gothic as fairguni. Additionally, the Slavic Perūn sends his axe or arrow from a mountain or the sky, and the Baltic tradition mentions a perpetual sacred fire maintained for Perkūnas in the forests or on hilltops.
A term for the sky, *h₂ekmōn, denoted both "stones" and "heaven". The motif of the stony skies can be found in the story of the Greek Akmon, the father of Ouranos and the personified Heaven. His name meant "a block of stone or metal designed to withstand a battering". Other cognates appear in Vedic áśman, Iranian asman, Lithuanian akmuõ, and possibly in Germanic *hemena. The association can be explained by the observation (or delusion) that certain stones had fallen from the sky: the word áśman is used for Indra’s weapon, and the thunderstone is called Perkūno akmuo ("Perkuna's stone") in Lithuanian tradition.
The following cognates stem from the root *Perkwunos and are associated with a weather-god in Western Indo-European mythologies:
- Lithuanian: Perkūnas, the god of rain and thunder (with cognates in Latv. Pērkōns, Old Prus. Perkunis),
- Slavic: Perūn, the thunder-god (with cognates in ORus. Perunŭ, Belar. Piarun, Slovak Parom),
- Old Norse: Fjörgynn, the mother of the thunder-god Thor (from Ger. *Fergunja, "mountain", maybe "mountainous forest"; or the feminine equivalent of *ferga, "god"; with cognates in Goth. fairguni, "mountain range", OEng. fi(e)rgen- "mountain"; in any case from PIE *Perwunī).
Another cognate in Celtic is generally accepted:
- Gaulish: the Hercynian (Herkynío) mountains or forests, ancient name of the Ardennes (from Celt. *ferkunyo, ult. from PIE *perkwun(i)yā, the "realm of Perkwūnos").
Other cognates are less secured:
- Vedic: Parjanya, the god of rain, thunder and lightning (although Sanskrit sound laws rather predict a parkūn(y)a form; an original *pergénio has therefore been postulated, with a possible cognate in Slavic *per(g)ynia, "wooden hills"),
- Greek: Keraunos (κεραυνός), the name of Zeus’s thunderbolt, which were sometimes also deified (by metathesis of *per(k)aunos; although the root *ḱerh₂, "shatter, smash" has also been proposed),
- Albanian: Perëndi, a thunder-god (from perunŭ attached to *dyeus),
- Thracian: Perkos/Perkon (Περκων/Περκος), a horseman hero,
- Nuristani: Pärun/Pērūne, a war god.
Some scholars have argued that the motifs of Anatolian weather gods Tarḫunz or Tarḫunna stem from those of Perkwunos, but that Anatolians did not preserve the old name in favour of the epithet Tṛḫu-ent- ("conquering", from PIE *terh2, "to cross over, pass through, overcome"), which sounded close to the name of the Hattian Storm-god Taru.
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