Iran’s history is usually studied in two eras: before Islam and after Islam.
The pre-Islamic period contains five major dynasties: The Elamite with Susa as their capital city; The Medas who were the first to unify Iran politically, with their chief city being Ecbatana (modern Hamadan); The Achaemenids who made the Persian Empire by their first king Cyrus (559-539 BC), and expanded and organized by Darius the Great (522-486 BC).
It lasted until Alexander’s invasion in 330 BC. It evolved from Median state but was far greater in extent, bureaucracy, military, and economy. The Persian Empire was the first to contain, as Darius proudly says in his inscriptions “many people of many tongues”. By the end of Achaemenid period Persepolis (in Shiraz) was famous for being the richest and most beautiful city of the ancient world; The Partians royal family was firmly established in northeastern Iran by 200 BC, and by a century later it had reunified Iranian lands. The Partians continued the Achaemenids’ policy of tolerance and maintained their administrative system; and finally the Sasanians (sassanids) who ruled Persia from 224 to mid- seventh century AD. It was considered then that the civilized world was divided between the Persian and the Roman Empires.
The post-Islamic period: Arabs brought Islam to Iran. From the early ninth century local Iranian rulers and dynasties ruled over different parts of Iran.
The revival of Persian culture and artistic traditions began mainly during the Samanid rule in Khorasan, and continued during the rule of the Ghaznaids (977-1041). Persian literary activities, particularly in poetry, led to the recognition of the Persian language’s preeminence in Iran.
Turks began invading in the 10th century and soon established several Turkish states. The invasion of Turks was followed by the Mongols, led by Jenghiz Khan in the 13th century and Timur in the late 14th cent.
Safavid dynasty (1500-1735, with their capital mainly in Isfahan), was founded by Shah (king) Ismail. It was during this period, specially during the reign (1587-1629) of Shah Abbas that the majestic city of Isfahan was endowed with unprecedented glory and grandeur. A potent factor in the unification of Iran under Safavids was the adaptation of Shi’ism as the official sect of religion.
The Afghan invasion in 1722 led to a short period of chaotic rule in eastern Iran before Nader Shah (Afshar dynasty), an army officer, crowned himself king in 1736. However, this success was short- lived and was followed by another short- lived yet constructive dynasty , that of Zand dynasty (1750-1794, capital Shiraz), which saw the return of political stability and economic security, as well as a Safavid-style architectural renaissance, albeit on a smaller scale.
The Zands were succeded by Qajar dynasty (1795-1925, capital Tehran) a Turkish tribe who ruled Iran until the first quarter of the twentieth century.
The important event in the early 20th century in Iran was the rise of the constitutional movement and a constitution establishing a parliament was accepted by the king in 1906.
Reza Khan, founder of the Pahlavi dynasty (1926), and his son The Shah (Mohammad Reza) ruled Iran until 1978. In 1978, through the Islamic Revolution, people demanded the abolition of the monarchy and the return from exile of Ayatollah Khomeini. On return of The Ayatollah, following a referendum, Iran was declared as Islamic Republic on 1 April 1979. After Ayatollah Khomeini demised in 1989, Ayatollah Khamenei was selected as the Supreme Leader of the country.