Mitra-Varuna is a Proto-Indo-European God duo, this two gods represent the day and night respectively, and also the priesthood class.
Mythology[]
Hypothesis[]
The idea of Mithra-Varuna is based on the connections between many Indo-European deities, curiously this is more reflected in the Indo-Aryan religions like Hinduism and Zoroastrianism. In the Persian cosmogony Mithra was the Ahura Mazda (Varuna)´s right hand, in fact Mithra was the second most important god in Zoroastrianism, In the Vedic religion, Mithra was the companion of Varuna, where they are the protectors of Rta, some Hindus interpret this as a homosexual relationship.
Even in other Indo-European religions the concept of Mithra-Varuna is also present, in the Greek religion Zeus (Mithra) is the god of the Shining day in contracts with Uranus (Varuna) the god of night sky, in Germanic mythology Tyr was the king of the gods and Odin has an association with crows (a nocturne animal).
So, presumably the Proto-Indo-European Mithra-Varuna could have had similar characteristics with the Vedic Mithra-Varuna.
Day and Night[]
The relationship between Mithra and Varuna is due to their characteristics, so Mithra in many cultures is the god of the sun therefore he is the day, meanwhile Varuna is the night sky god because by his connection with the seas that are similar with the nightly Varuna become into the night god. Mithra-Varuna is by extension a dualist deity that represent the the cycle of day and night.
In the fakelore of Slavic mythology there exists a good example of Mithra-Varuna with that being the dualistic relationship of the gods Belobog and Chernobog.
Contracts[]
In the Indo-Aryan religions both Mithra and Varuna/Ahura Mazda, where the contract was very common in their religious cosmogony unlike with other Indo-Europeans religions, because for them the contracts was in the relationship with the divine, so Ahura Mazda in Zoroastrianism used contracts for making a moral pact with his worshipers, besides the contracts it was used by themes like justice, ethics and morality too.
Because the contracts in the Indo-Aryan religions were fundamental for the ethic, morality and relationship with the divinity, therefore the original Proto-Indo-European could have had a religious vision similar to the modern Indo-Aryan religions.
Legacy[]
Modern Hinduism[]
Mithra although is no longer relevant, his legacy still exists in the name Mithra that is used for some deities, meanwhile Varuna is still relevant in Hinduism along with the other surviving Vedic deities like Agni and Indra.