List of ancient great powers
The Sassanid Empire is the name used for the fourth Iranian dynasty, and the second Persian Empire (226–651). The empire's territory encompassed all of today's Iran, Iraq, Armenia, Afghanistan, eastern parts of Turkey, and parts of Syria, Pakistan, and large parts of Caucasia, Central Asia and Arabia. During Khosrow II's rule in 590–628 Egypt, Jordan, Palestine, Lebanon were also briefly annexed to the Empire, as well as far west as western Asia Minor. The Sassanid era, encompassing the length of the Late Antiquity period, is considered to be one of the most important and influential historical periods in Iran. In many ways the Sassanid period witnessed the highest achievement of Persian civilization. The empire is furthermore known for being the arch-rival of the neighboring Roman–Byzantine Empire for a period of over 400 years. As the Parthians were replaced by the Sassanids, they carried on the already century long lasting Roman–Persian Wars, which would eventually become the longest conflict in human history.
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.