section_path: History by region/West Asia/Iranian peoples
section_name: Iranian peoples
paragraph_text: Iranian peoples
  
  The Medes and Persians were peoples who had appeared in the Iranian plateau around 1500 BC. Both peoples spoke Indo-European languages and were mostly pastoralists with a tradition of horse archery. The Medes established their own Median Empire by the 6th century BC, having defeated the Neo-Assyrian Empire with the Chaldeans in 614 BC.
  
  The Achaemenid Empire was founded by Cyrus the Great, who first became king of the Persians, then conquered the Medes, Lydia, and Babylon by 539 BC. The empire built on earlier Mesopotamian systems of government to govern their large empire. By building roads, they improved both the ability to send governmental instructions throughout their lands as well as improving the ability of their military forces to be deployed rapidly. Increased trade and upgraded farming techniques increased wealth, but also exacerbated inequalities between social classes. The empire's location at the centre of trading networks spread its intellectual and philosophical ideas throughout a wide area, and its religion, while not itself spreading far, had an impact on later religions such as Christianity, Islam, and Judaism. Cyrus' son Cambyses II conquered Egypt, while a later emperor, Darius the Great, expanded the empire to the Indus River, creating the largest empire in the world to that date. But Darius and his son Xerxes I failed to expand into Greece, with expeditions in 490 and 480 BC eventually failing. The Achaemenid dynasty and empire fell to Alexander the Great by 330 BC, and after Alexander's death, much of the area previously ruled by the Cyrus and his successors was ruled by the Seleucid dynasty.
  
  Parthia was an Iranian civilisation situated in the northeastern part of modern Iran. Their power was based on a combination of military power based on heavy cavalry with a decentralised governing structure based on a federated system. The Parthian Empire was led by the Arsacid dynasty, which by around 155 BC under Mithradates I had mostly conquered the Seleucid Empire. Parthia had many wars with the Romans, but it was rebellions within the empire that ended it in the 3rd century AD.
  
  The Sasanian Empire began when the Parthian Empire ended in AD 224. Their rulers claimed the Achaemenids as ancestors and set up their capital at Ctesiphon in Mesopotamia. Their period of greatest military expansion occurred under Shapur I, who by the time of his death in AD 272 had defeated Roman imperial armies and set up buffer states between the Sasanians and Roman Empires. After Shapur, the Sasanians were under more pressure from the Kushans to their east as well as the Roman then Byzantine Empire to its west. However, the Sasanians rebuilt and founded numerous cities and their merchants traveled widely and introduced crops such as sugar, rice, and cotton into the Iranian plateau. But in AD 651, the last Sassanid emperor was killed by the expanding Islamic Arabs.