Some linguists have proposed that the Thracian branch of IE was specifically related to Baltic. We are generally sympathetic to that view – in the least we see it as being a sister group to Balto-Slavic to the exclusion of Indo-Iranian. Of course, there is little we can do about testing this conjecture from a linguistic standpoint because Thracian is dead and gone. However, this opens another line of investigation.
The Greek tradition records a key hymn composer, Orpheus, the son of Oeagrus, as being a Thracian. The Orphic hymn collection was an important scriptural body for the yavana-s that continued to be studied and interpreted down to the last of their great thinkers, Damascius. While like the Hindu ṛṣi-s, Orpheus and Orphic material have acquired a great overburden of later accretion, there might be some uniquely Thracian-inspired elements atवा its core.
We believe the protogonic deity “the very august divinity” according to Damascius who “carried the seed of the gods, the famous Erikepaius” is one such. He is said to have been swallowed whole by Zeus who absorbed him into his limbs with his allness. This Erikepaius is a likely ortholog of none other than our Vṛṣākapi, who is celebrated in RV 10.86. He is described as a friend of Indra and was later identified with Viṣṇu (we do not know if that identification already existed in the RV). The great patriot Tilak identified him with the Orion region of the sky that is more commonly associated with the Hindu protogonic deity Prajāpati. We agree that this is a valid identification, and it suggests a link between the two in the ancient past. We also suspect that in the last ṛk of the sūkta, there is an allusion to the human genesis via Manu’s daughter Parśu (mother of the Iranians?) that gives a protogonic link. We believe that Vṛṣākapi is a rare surviving memory of a protogonic entity linked to Indra in the RV and incorporated into Zeus in the Greek world.
This protogonic deity probably emerged in the ancestor of the Indo-Irano-Thraco-Balto-Slavic clade of IE and was relatively strong among the Thracians while fading out elsewhere or being revived under a new disguise as Prājāpatya deities of the Ārya world. However, the statement by Indra: “yasyedam apyaṃ haviḥ priyaṃ deveṣu gacchati” – the watery haviṣ might be linked to the carrying of the seed of the gods by Erikepaius.