The earliest archaeological findings from Persia date to the Paleolithic era, 100,000 years ago. By 5000 BCE, Persia hosted sophisticated agriculture and early cities.Powerful dynasties have ruled Persia, beginning with the Achaemenid (559-330 BCE), which was founded by Cyrus the Great.
Alexander the Great conquered Persia in 300 BCE, founding the Hellenistic era (300-250 BCE). This was followed by the indigenous Parthian Dynasty (250 BCE - 226 CE) and the Sassanian Dynasty (226 - 651 CE). In 637, Muslims from the Arabian peninsula invaded Iran.
Zoroastrianism faded away as more and more Iranians converted to Islam. During the 11th century, the Seljuk Turks conquered Iran bit by bit, establishing a Sunni empire.
The Seljuks sponsored great Persian artists, scientists and poets, including Omar Khayyam. In 1219, Genghis Khan and the Mongols invaded Persia, wreaking havoc across the country and slaughtering entire cities. Mongol rule ended in 1335, followed by a period of chaos. In 1381, a new conqueror appeared: Timur the Lame or Tamerlane. He too razed entire cities; after just 70 years, his successors were driven from Persia by the Turkmen. In 1501, the Safavid dynasty brought Shia Islam to Persia.
The ethnically Azeri/Kurdish Safavids ruled until 1736, often clashing with the powerful Ottoman Turkish Empire to the west. The Safavids were in and out of power throughout the 18th century, with the revolt of former slave Nadir Shah and the establishment of the Zand dynasty. Persian politics normalized again with the founding of the Qajar Dynasty (1795-1925) and Pahlavi Dynasty (1925-1979). In 1921, the Iranian army officer Reza Khan seized control of the government. Four years later, he ousted the last Qajar ruler and named himself Shah. This was the origin of the Pahlavis, Irans final dynasty. His son, Mohammad Reza Pahlavi, took the throne in 1941. The new shah ruled until 1979, when he was overthrown in the Iranian Revolution. Soon, the Shia clergy took control of the country, under the leadership of the Ayatollah Ruhollah Khomeini. Ayatollah Ruhollah Khomeini. declared Iran a theocracy, with himself as the Supreme Leader. He ruled the country until his death in 1989; he was succeeded by Ayatollah Ali Khamenei.