Life In Iran

Further separation of Proto-Iranians into "Eastern" and "Western" groups occurred due to migration. By the first millennium BC, Medes, Persians, Bactrians and Parthians populated the western part, while Cimmerians, Sarmatians and Alans populated the steppes north of the Black Sea.
Other tribes began to settle on the eastern edge, as far as on the mountainous frontier of the north-western Indian subcontinent and into the area which is now Balochistan. Others, such as the Scythian tribes, spread as far west as the Balkans and as far east as Xinjiang. Avestan is an eastern Old Iranian language that was used to compose the sacred hymns and canon of the Zoroastrian Gathas in c. 1000 BC.
• Pre-Islamic statehood (625 BC – 651 AD)
The Medes are credited with the unification of Iran as a nation and empire (625–559 BC), the largest of its day, until Cyrus the Great established a unified empire of the Medes and Persians leading to the Achaemenid Empire (559–330 BC), and further unification between peoples and cultures. After Cyrus' death, his son Cambyses II continued his father's work of conquest, making significant gains in Egypt.