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.
Persian people
The ancient Persians were a nomadic branch of the Iranian population that, in the early 10th century BC, settled to the northwest of modern-day Iran. They were initially dominated by the Assyrians for much of the first three centuries after arriving in the region. However, they played a major role in the downfall of the Neo-Assyrian Empire. The Medes, another branch of this population, founded the unified empire of Media as the region's dominant cultural and political power in c. 625 BC. Meanwhile, the Persian dynasty of the Achaemenids formed a vassal state to the central Median power. In c. 552 BC, the Achaemenids began a revolution which eventually led to the conquest of the empire by Cyrus II in c. 550 BC. They spread their influence to the rest of what is called the Iranian Plateau, and assimilated with the non-Iranian indigenous groups of the region, including the Elamites and the Mannaeans.
At its greatest extent, the Achaemenid Empire stretched from parts of Eastern Europe in the west, to the Indus Valley in the east, making it the largest empire the world had yet seen. The Achaemenids developed the infrastructure to support their growing influence, including the creation of Pasargadae and the opulent city of Persepolis. The empire extended as far as the limits of the Greek city states in modern-day mainland Greece, where the Persians and Athenians influenced each other in what is essentially a reciprocal cultural exchange. Its legacy and impact on the kingdom of Macedon was also notably huge, even for centuries after the withdrawal of the Persians from Europe following the Greco-Persian Wars. The empire collapsed in 330 BC following the conquests of Alexander the Great, but reemerged shortly after as the Parthian Empire.