The history of Iran, also known as Persia has been closely connected with the history of a larger historical region, from Egypt in the west to the Indus Valley and Syr Darya in the east, and from the Caucasus and Eurasian Steppe in the north to the Persian Gulf in the south.

Throughout ancient history, the Greeks, Arabs, Turk, and Mongols had taken turns in invading Iran.Therefore, Iran continually had to acknowledge and claim its identity as it evolved into a unique political and cultural entity.

Iran is one of the oldest continuous major civilizations, dating back to 4000 BCE.

The Medes unified Iran as a nation and empire in 625 BCE.The Achaemenid Empire (550-330 BCE ) was the first Persian empires to rule from the Balkans to North Africa and also Central Asia from their capital in Persis (Persepolis ).They were succeeded by the Seleucid Empire, Parthians and Sassanids who governed Iran for almost 1,000 years. Iran became Islamic during 8^th to 10^th century and ended the Sassanid Empire. It led to the eventual decline of the Zoroastrian religion in Persia.

After centuries of foreign occupation and short-lived native dynasties, Iran was once again reunified as an independent state in 1501 by the Safavid dynasty Shi’s Islam became the official religion of their empire, marking one of the most important turning points in the history of Islam. Iran had been a monarchy ruled by a shah, or emperor, almost without interruption from 1501 until the 1979 Iranian revolution, when Iran officially became an Islamic Republic on 1 April 1979.