title: History of Iran
context: Iran is home to one of the world's oldest continuous major civilizations, with historical and urban settlements dating back to 7000 BC.[1] The southwestern and western part of the Iranian Plateau participated in the traditional Ancient Near East with Elam, from the Early Bronze Age, and later with various other peoples, such as the Kassites, Mannaeans, and Gutians. Georg Wilhelm Friedrich Hegel calls the Persians the "first Historical People".[2] The Medes unified Iran as a nation and empire in 625 BC.[3] The Achaemenid Empire (550–330 BC), founded by Cyrus the Great, was the first Persian empire and it  ruled from the Balkans to North Africa and also Central Asia, spanning three continents, from their seat of power in Persis (Persepolis). It was the largest empire yet seen and the first world empire.[4] The First Persian Empire was the only civilization in all of history to connect over 40% of the global population, accounting for approximately 49.4 million of the world's 112.4 million people in around 480 BC.[5] They were succeeded by the Seleucid, Parthian, and Sasanian Empires, who successively governed Iran for almost 1,000 years and made Iran once again as a leading power in the world. Persia's arch-rival was the Roman Empire and its successor, the Byzantine Empire.
question: When did the Persian empire come into existance?
answers: 550–330 BC