section_path: History
section_name: History
paragraph_text: History
  
  Iran is home to one of the world's oldest continuous major civilizations, with historical and urban settlements dating back to 4000 BC. The western part of the Iranian plateau participated in the traditional ancient Near East with Elam (3200–539 BC), and later with other peoples such as the Kassites, Mannaeans, and Gutians. Georg Wilhelm Friedrich Hegel called the Persians the "first Historical People". The Iranian Empire began in the Iron Age with the rise of the Medes, who unified Iran as a nation and empire in 625 BC. The Achaemenid Empire (550–330 BC), founded by Cyrus the Great, was the largest empire the world had seen, spanning from the Balkans to North Africa and Central Asia. They were succeeded by the Seleucid, Parthian, and Sasanian Empires, who governed Iran for almost 1,000 years, making Iran a leading power once again. Persia's arch-rival during this time was the Roman Empire and its successor, the Byzantine Empire.
  
  Iran endured invasions by the Macedonians, Arabs, Turks, and Mongols. Despite these invasions, Iran continually reasserted its national identity and developed as a distinct political and cultural entity. The Muslim conquest of Persia (632–654) ended the Sasanian Empire and marked a turning point in Iranian history, leading to the Islamization of Iran from the eighth to tenth centuries and the decline of Zoroastrianism. However, the achievements of prior Persian civilizations were absorbed into the new Islamic polity. Iran suffered invasions by nomadic tribes during the Late Middle Ages and early modern period, negatively impacting the region. Iran was reunified as an independent state in 1501 by the Safavid dynasty, which established Shia Islam as the empire's official religion, marking a significant turning point in the history of Islam. Iran functioned again as a leading world power, especially in rivalry with the Ottoman Empire. In the 19th century, Iran lost significant territories in the Caucasus to the Russian Empire following the Russo-Persian Wars.
  
  Iran remained a monarchy until the 1979 Iranian Revolution, when it officially became an Islamic republic on 1 April 1979. Since then, Iran has experienced significant political, social, and economic changes. The establishment of the Islamic Republic of Iran led to the restructuring of its political system, with Ayatollah Khomeini as the Supreme Leader. Iran's foreign relations have been shaped by the Iran–Iraq War (1980–1988), ongoing tensions with the United States, and its nuclear program, which has been a point of contention in international diplomacy.