Summary

Achaemenid Empire (550–330 BCE):

Founded by Cyrus the Great, it stretched from the Balkans to the Indus Valley, known for administrative brilliance and tolerance. Conquered by Alexander the Great.

Seleucid Empire:

Rose after Alexander but declined due to instability.

Parthian Empire (247 BCE–224 CE):

Famous for cavalry and resisting Rome.

Sassanian Empire (224–651 CE):

A cultural peak with advances in art and science, ended by Arab conquests.

Modern Iran:

Renamed in 1935 under Reza Shah Pahlavi, modernized until the 1979 Islamic Revolution established the current Islamic Republic.