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.
History of Iran
Most of the Sassanian Empire's lifespan it was overshadowed by the frequent Byzantine–Sasanian wars, a continuation of the Roman–Parthian Wars and the all-comprising Roman–Persian Wars; the last was the longest-lasting conflict in human history. Started in the first century BC by their predecessors, the Parthians and Romans, the last Roman–Persian War was fought in the seventh century. The Persians defeated the Romans at the Battle of Edessa in 260 and took emperor Valerian prisoner for the remainder of his life.