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.
Iran (word)
During the Safavid era (1501–1736), most of the territory of the Sasanian empire regained its political unity, and Safavid kings were assuming the title of ""Šāhanšāh-e Irān"" (Iran's king of kings). An example is Mofid Bafqi (d. 1679), who makes numerous references to Iran, describing its border and the nostalgia of Iranians who had migrated to India in that era. Even Ottoman sultans, when addressing the Aq Qoyunlu and Safavid kings, used such titles as the “king of Iranian lands” or the “sultan of the lands of Iran” or “the king of kings of Iran, the lord of the Persians”. This title, as well as the title of ""Šāh-e Irān"", was later used by Nader Shah Afshar and Qajar and Pahlavi kings. Since 1935, the name "Iran" has replaced other names of Iran in the western world. Jean Chardin, who travelled in the region between 1673 and 1677, observed that "the Persians, in naming their country, make use of one word, which they indifferently pronounce "Iroun", and "Iran". [...] These names of Iran and Touran, are frequently to be met with in the ancient histories of Persia; [...] and even to this very day, the king of Persia is call'd "Padsha Iran" ["padshah"='king'], and the great vizier, "Iran Medary" [i.e. "medari"='facilitator'], the Pole of Persia"".