(pronounced as Eeraan) - The ancient Vaidik India included this place what later became Iran, Hindukush mountains, and because of a flood, the people were led by Manu to Sapt Sindhu region. In due course, because of the development of a Schism, one group led by a Rishi Ushanaa (Shukra*) left the Sapt Sindhu region and settled what later became Iran. 

Avestaa and Vendidaad - the two holy books of Iranian religion existing before Islam contain ample proof that the Aarya of Sapt Sindhu and Iranian people were the same at one time. A descendent of Ushanas Shukra, Kavi Shukra has been mentioned as one of their kings. Some of the names of Divinities and historical persons found are common, such as "Asur Madhiraa" (Asur Mazadaa); Saraswatee (Harahvatee); Indra (Indar); Vritrahan (Berethragn); Yam (Yim); Som (Haom); Atharv (Athrav); Gandharv (Ganderv); Vivaswaan (Vivanhvant). The Iranian word "Jashn", still popular in north India, is a corrupt word of Sanskrit word "Yasn" which is the same as Yagya.

Some descendents of Ushanas Shukra wanted to use the word A-Sur for God, but many opposed to it. In the early Vaidic period, this word was used several times for "mighty" for God, but later on it was reserved by one section for Daitya. When the group, worshipping God as A-Sur, left Sapt Sindhu region, the remaining people coined the word "Sur" for God, and A-Sur for Daitya. Before converting to Islam, much of Iran, including Afgaanistaan, was Buddhist.

Those people who strongly believed in original Vaidik religion, which was called Zoroastrian religion, left their homeland in boats and sought refuge in India and were called as Paarasee community Like Hindoo, Paarasee worship around sacred fire; and what is "Yagya" to Vaidik Hindu, is called "Yashn" by Paarasee.

The six basic principles of Paarasee's religion further confirm that their religion, which they call Zoroastrianism, is really Vaidik. They are - 

(1) Ameritat (Amritatwa in Sanskrit) - immortality
(2) Khshaatra (Kshaatra in Sanskrit) - power
(3) Vohu Manah (Vasumanah in Sanskrit) - good mind
(4) Aash (Aarsh in Sanskrit) - virtue
(5) Armaiti (Arimati in Sanskrit) - proper mind, and
(6) Haarvatat (Swaasthya in Sanskrit) - health.
(Aangiras, p 76)

* My Note - I suppose by Ushanaas Shukra, Aangiras means Shukraachaarya Jee, as on p 87-88, under the entry of Ushanas Shukra, he mentions that Devayaanee was his daughter and she was married to king Yayaati.