The following myths preserve a remarkable pattern of tripartation. In part they conform to Dumezil’s archetype of tripartation in the Indo-European world.
1)pa~nchavimsha brAhmaNa 18.9.1
Of varuNa, after he was consecrated, his fiery luster (bharga) departed. It fell asunder in 3 parts: 1/3rd became bhR^igu, the second 1/3rd became the shrAyantIya sAman, the final 1/3rd entered water.
2)aitareya brAhmaNa 3.33-34
rudra shot his 3 pointed arrow and slew prajApati who was running towards his own daughter. The semen of prajApati ran out and formed a pond. The gods decreed that the semen of prajApati should not go waste. They surrounded it with agni and asked the maruts to blow upon it. But it did not move. So they surrounded it with agni vaishvAnara and asked the maruts to blow upon it. The seed split up into 3 parts. The first part became the yonder Aditya. The second part became the bhR^igu and varuNa took him, and the 3rd part that was brilliant became the Adityas. From the glowing embers of this blaze A~ngiras arose.
3)Yasht 19.31-38 of the Iranian Avesta.
The awesome divine luster, Hvarena, was generated by the great god Ahura Mazda and it became manifest in the great Yima Vaivanghant, who then lost a third of it as his decline began. This lost Hvarena departed in the form of the Varaghna bird and was taken up by the god Mithra. The next third again departed as a Varaghna bird and was seized by the valiant Thraetaona Athwya. Powered by this Hvarena he slew Azhi Dahaka. The last third of the Hvarena also departed as a Varaghna from Yima and was taken up by the great hero Keresaspa. Powered by this Hvarena he slew the Gandarewa Zairi-Pashnem. Then he slew the great demon Snavidhaka, who was attempting to destroy Spenta Mainyu.
The Yasht goes on to narrate that this Hvarena was finally placed deep in water by Apam Napat who is in the form of the speeding horse (Aurvat-Aspa). It also adds that “Whosoever of you, O men, shall seize that Xvarena, he is an Athravan.”
The hvarena placed in water by Apam Napat in the Avestan account, swells up thrice, when the Turanian Frangrasyan (an enemy of the Aryans) unsuccessfully tries to seize it, and it spills the water over forming 3 new streams.
Here the secondary motif of the birds bearing away the Hvarena of the fallen Yima also persists in the Indo-Aryan world. When indra beheads trishiras one bird emerges from each of his 3 heads and departs bearing his prANa.
4) We get another slightly more distant instance of tripartite loss of power or luster in the Indo-Aryan world again in the pa~nchavimsha brAhmaNa (20.18) and the jaiminiya brAhmaNa in explaining the offerings to viShNu and indra in garga rite. When indra attacked v^Ritra with his vajra he said he would give up his 1/3rd of his splendor if indra did not slay him. And, when he did so viShNu accepted it. Again indra attacked and he gave it up a 1/3rd of his splendour, which was taken up by viShNu. Finally, he gave up the last 3rd of his splendour in the final attack by indra, which too was absorbed by viShNu. Thus undefeated indra conquered the demon. In the rite indra is made 2/3rd of the offerings while viShNu, his younger brother, receives 1/3rd.
Farther away in the Indo-European world, this reappears in faraway Ireland in the tale of Nechtan and Boand. Nechtan on of the Tuatha de Danann had a pretty wife called Boand and a magical well that no one other than his 3 cup-bearers could approach. The rest were blinded by a fiery luster emanating from it. Boand filled with pride over her beauty approached it and circumambulated it 3 times counterclockwise, when 3 fierce waves leapt out of it. The first shattered her foot, the second destroyed her beautiful eye and the 3rd smashed her hand. She was chased by the three-fold stream overflowing from the well and it drowned her in the sea. A point to note here is that Nechtan is the Irish cognate of apAM napAt of the vedas and the Avesta .
5) Finally, we may follow the lead back to the ancient hymn of gR^itsamada shunahotra shaunaka bhArgava to apAM napAt (RV 2.35).
samanyA yantyupa yantyanyAH samAnaM UrvaM nadyaH pR^iNanti |
tamU shuciM shucayo dIdivAMsamapAM napAtaM pari tasthurApaH ||
Translation: Some streams unite themselves and others join them: as rivers, they flow together to propitiate Urva (the fire within water).On every side the bright streams have encompassed the bright and resplendent apAM napAt.
asmai tisro avyathyAya nArIrdevAya devIrdidhiShantyannaM |
kR^itA ivopa hi prasarsre apsu sa pIyUShaM dhayati pUrvasUnAm ||
Translation: Three goddesses present food to that unassailable god; as if formed in the waters they spread all over, and he drinks the colostrum of the first-emergent.
The term “Urva” immediately makes the link to the tale narrated in the Adi parva of the mahAbhArata regarding the great bhArgava R^ishi aurva. Furious over the killing of his clansmen by the haihayas, the young aurva generated a kshatriya-destroying fire that consumed the haihayas. When it continued to rage the ancestors of aurva appeared and asked him to cast the fire away into the ocean. He did so, and it assumed the form of a head of horse. This horse-head termed the vADavamukha, from whose mouth the submarine fire is supposed to blaze forth. This chain of links is finally completed by the phrase in the above-mentioned R^igvedic hymn of gR^itsamada: apAM napAt is called “ashvasyAtra janimAsya”, i.e. the source of the horse.
This motif of a blazing horse head is recycled in the Hindu mythosphere in the tale of the of the death of kAma from the shiva purANa. When kAma tried to influence shiva, the latter blazed forth in wrath and let out the fire from his third eye. The fire consumed kAma and then assuming the form of a head of a horse entered the southern ocean where it remains as a submarine fire.
6) Interestingly the horse’s head in waters reappears in Germanic folklore showing the tenacity of this mythic motif. Grimm narrates a tale of people trying to fathom the depth of the Huntsoe Lake. They tied a ploughshare to a rope and lowered it into the lake. But from below came a ghostly voice threatening them with fatal consequence if they tried. In terror they hauled the rope back and found that a skull of a horse was fastened to it in place of the ploughshare!
To sum up we see many different mythic motifs seamless merge into each other with a wide spread in the Indo-European world. The clearest preservation in the Indo-Iranian world but the motifs can be detected in other Indo-European mythologies suggesting a clear ancient origin in the common ancestor of the Indo-Europeans.
The motifs are: 1) The divine luster or glory departs from its holder in 3 parts. 2) One or more of these parts enters water and rests within it. 3) The part lying in water is often linked to the form of a horse.
Myth is modular and the units of myth can often recombine with others, just as domains in proteins!