Hi all
This is a slightly different topic and you might find some overlap on history and mythology here
We might know that the ancient Persians (pre Islamic) followed a religion which worshipped Ahur Mazda (in fact there are still few people of this sect) called as Zoroastrians. Few prominent ones are Tatas and Godrej families
There is a deep connect between the followers of Vedas and Zoroastrians. If you see the language of Avesta, the most pious book of Zoroastrians and that of Vedas you would find huge similarities. The language is so similar that Vedic Sanskrit is closer to the Avesta language than to the Classical Sanskrit which is the language of Puranas, later Upanishads and epics like Ramayan and Mahabharat
There is one major difference though, the usage of word "s", Avesta has very few instances of sound "s", they generally have "h" sound instead. For example the word dasyu of Vedas become dahyu in Avesta, Sapta Sindhu of Vedas become Hapta Hindu in Avesta. And Asurs in Vedas become Ahur in Avesta...
The difference however. While in Vedas Asur are demons and Devas are Gods, in Avesta Ahur is God and Deovas are demons. While we do not find the name Zoroaster in Vedic texts, there is references of Indar (chief Vedic deity) in Avesta as a Demon
Also Shukracharya is mentioned as Daitya Guru (guru of Asurs) in Indic text, he is called as Usaana Rishi a term also found in Avesta with respect as a great Poet..
Not just this deities like Mithra and Varuna are actually common in both the religions(in lack of better word)...
This indicates that definitely earlier both these groups were together. They were actually the same people who later drifted into two groups one worshipping Indra and other not ..
Different scholars have different theories on when and where they drifted...
Talagiri actually mentions 10 kings war (Dashragya) when people moved across but his points are generally not considered very true
Please share in any details you might know