https://en.m.wikipedia.org/wiki/Indo-European_migrations

https://en.m.wikipedia.org/wiki/Indo-Aryan_migration

https://en.m.wikipedia.org/wiki/Sintashta_culture

https://en.m.wikipedia.org/wiki/Historical_Vedic_religion

https://en.m.wikipedia.org/wiki/Mitra_(Vedic)

in Indo-Iranian (Vedic) Mitra means that which causes to bind, covenant, contract, oath. The protection of which is Mitra's role in both the "Rigveda" and in the "Mitanni Treaty".

https://en.m.wikipedia.org/wiki/Mitanni#Shattiwaza_/_Kurtiwaza

https://en.m.wikipedia.org/wiki/Mitanni-Aryan

The names of the Mitanni aristocracy frequently are of Indo-Aryan origin, and their deities also show Indo-Aryan roots..

(Mitra, Varuna, Indra)

https://en.m.wikipedia.org/wiki/Ṛta

https://en.m.wikipedia.org/wiki/Me_(mythology)