Literature in Iran
Persian is Iran's official language and the language of the country's ethnic majority (i.e., the Persians), and Persian literature has been the country's most influential literary tradition. Apart from Iran, Persian literature was used and developed further through several medieval Persianate societies in Asia Minor, Central Asia, and South Asia, and the language is still used widely in Central Asia (Tajikistan and Uzbekistan) and Afghanistan.
Greater Iran
Because the Achaemenid Empire or "First Persian Empire" was the successor state to the empires of Assyria and Babylonia based in Iraq, and because Elam is part of Iran, the ancient people of Iran were ruled by ancient Mesopotamians, which explains the close proximity between the people of south western Iran and the Iraqis even in modern days, in fact, the people of that part of Iran speak Mesopotamian Arabic and were put under the rule of modern Iran by the British. The ancient Persians adopted the Babylonian cuneiform script and modified it to write their language, along with adopting many other facets of ancient Iraqi culture, including the Aramaic language which became the official language of the Persian Empire.