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.
Name of Iran
The Greeks (who had previously tended to use names related to "Median") began to use adjectives such as (), () or () in the fifth century BC to refer to Cyrus the Great's empire (a word understood to mean "country"). Such words were taken from the Old Persian "Pārsa" – the name of the people from whom Cyrus the Great of the Achaemenid dynasty stemmed and over whom he first ruled (before he inherited or conquered other Iranian Kingdoms). Thus, the term "Persian" is an exonym and Iranians never historically referred to Iran by that exonym. The Pars tribe gave its name to the region where they lived (the modern day province is called Fars/Pars) but the province in ancient times was smaller than its current area. In Latin, the name for the whole empire was "Persia", while the Iranians knew it as "Iran" or "Iranshahr".