The plateau of Iran is among the oldest civilization centers of antic era in Asia, and has an important place in archeology science. The history of settlement in the plateau of Iran from new Stone Age till migration of Aryans is not yet very clear. But there are reliable evidences, which indicate that Iran has been inhabited since a very long time ago. Settlement centers have emerged close to water resources like springs and rivers or totally close to Alborz and Zagross Mountains.
Migration of Aryan clans to the plateau of Iran began since 2nd millennium BC. Out of these tribes, Parthians dwelled in Khorasan, Medes in the west, and Parsees resided in the south of Iran. The Median Empire rose in Hegmataneh (present Hamadan). The Achaemenidae established the first great Iranian Empire after defeating the Medians and conquest of their capital. The limits of the Achaemenian territory in the reign of Dariush I (522-485 BC), extended from the Plain of Sand River in the east to the borders of Greece at the west. Passargad and Persepolis are the vestiges of this period and are among the most important historical places as well as the significant tourism attractions of Iran. Thousands of tourists visit these places annually.
After the decline of the Achaemenian dynasty, and destruction of Persepolis by Alexander, his successors (Solookis) dominated over Iran for a short time. During this period the interaction of Iranian and Hellenic cultures happened. Around the year 250 BC. The Parthians, who were one of Aryan tribes as well as horse riders, advanced from Khorasan towards the west and south-west and founded their empire over Iran plateau in Teesfoon. This empire sustained till the year 224 AD. The Saasanides, after defeating the last Parthian king in 225 AD, founded a new empire which lasted till mid 7th century AD. The ancient period of Iran, regarding its political, social, and cultural characteristics, is one of the most magnificent epochs of Iranian history. Out of this era, there have remained so many cultural heritage and historical buildings in Persepolis, Passargad, Susa (Shoosh), Shooshtar, Hamedan, Marvdasht, Taghbostan, Sarvestan, and Nayshabour which are worth-seeing.
Emergence and influence of Islam in Iran happened in early 7th century AD., after the decline of Sassanid Empire. Since then, new era began in the history of Iran which caused severe fundamental evolution in social, political, religious, governmental, and public conditions of the country.
History of Iran is the history of ups and downs and along the history, so many empires and dynasties have governed over this country.