Ancient Iranian peoples in the context of "Ordos Plateau"

The Achaemenid Empire (/əˈkiːmənɪd/ ə-KEE-mə-nid; Old Persian: 𐎧𐏁𐏂, Xšāça, lit. 'The Empire' or 'The Kingdom') was an ancient Iranian empire founded by Cyrus the Great of the Achaemenid dynasty in 550 BC. At peak, its territorial extent was roughly 5.5 million square kilometres (2.1 million square miles), making it the largest empire of its time. Based in the Iranian plateau, it stretched from the Balkans and Egypt in the west to the Indus Valley in the east, including Anatolia, Cyprus, Mesopotamia, the Levant, parts of Eastern Arabia, and large parts of Central Asia.

By the 7th century BC, the region of Persis, located in the southwestern part of the Iranian plateau, had been settled by Persians. From Persis, Cyrus rose and defeated Media, Lydia, and the Neo-Babylonian Empire, thus marking the establishment of a new imperial polity in the ancient Near East. While its conquests were largely successful in most regions, the Achaemenid Empire's attempts to expand into Greece proved extremely difficult over the course of decades of wars and multiple kings, ultimately resulting in its defeat in the Greek mainland.

The Scythians (/ˈsɪθiən/ or /ˈsɪðiən/) or Scyths (/ˈsɪθs/), also known as the Pontic Scythians, were an ancient Eastern Iranic equestrian nomadic people who migrated during the 9th to 8th centuries BC from Central Asia to the Pontic Steppe in modern-day Ukraine and Southern Russia, where they remained until the 3rd century BC.

Skilled in mounted warfare, the Scythians displaced the Agathyrsi and the Cimmerians as the dominant power on the western Eurasian Steppe in the 8th century BC. In the 7th century BC, the Scythians crossed the Caucasus Mountains and often raided West Asia along with the Cimmerians.

The Sarmatians (/sɑːrˈmeɪʃiənz/; Ancient Greek: Σαρμάται, romanized: Sarmátai; Latin: Sarmatae [ˈsarmatae̯]) were a large confederation of ancient Iranian equestrian nomadic peoples who dominated the Pontic steppe from about the 5th century BC to the 4th century AD.

The earliest known reference to the Sarmatians occurs in the Avesta, where they appear as Sairima-, which in later Iranian sources becomes Sarm and Salm. Originating in the central parts of the Eurasian Steppe, the Sarmatians formed part of the wider Scythian cultures. They started migrating westward around the fourth and third centuries BC, coming to dominate the closely related Scythians by 200 BC. At their greatest reported extent, around 100 BC, these tribes ranged from the Vistula River to the mouth of the Danube and eastward to the Volga, bordering the shores of the Black and Caspian seas and the Caucasus to the south.

Aryan (/ˈɛəriən/), or Arya (borrowed from Sanskrit ārya), is a term originating from the ethno-cultural self-designation of the Indo-Iranians. It stood in contrast to nearby outsiders, whom they designated as non-Aryan (*an-āryā). In ancient India, the term was used by the Indo-Aryan peoples of the Vedic period, both as an endonym and in reference to a region called Aryavarta (lit. 'Land of the Aryans'), where their culture emerged. Similarly, according to the Avesta, the Iranian peoples used the term to designate themselves as an ethnic group and to refer to a region called Airyanem Vaejah (lit. 'Expanse of the Arya'), which was their mythical homeland. The word stem also forms the etymological source of place names like Alania (*Aryāna) and Iran (*Aryānām).

Although the stem *arya may originate from the Proto-Indo-European language, it seems to have been used exclusively by the Indo-Iranian peoples, as there is no evidence of it having served as an ethnonym for the Proto-Indo-Europeans. The view of many modern scholars is that the ethos of the ancient Aryan identity, as it is described in the Avesta and the Rigveda, was religious, cultural, and linguistic, and was not tied to the concept of race.

The Massagetae or Massageteans, also known as Sakā Tigraxaudā or Orthocorybantians, were an ancient Eastern Iranian Saka people who inhabited the steppes of Central Asia and were part of the wider Scythian cultures. The Massagetae rose to power in the 8th to 7th centuries BCE, when they started a series of events with wide-reaching consequences by expelling the Scythians out of Central Asia and into the Caucasian and Pontic Steppes. The Massagetae are most famous for their queen Tomyris's alleged defeating and killing of Cyrus, the founder of the Persian Achaemenid Empire.

The Massagetae declined after the 3rd century BCE, after which they merged with some other tribes to form the Alans, a people who belonged to the larger Sarmatian tribal confederation, and who moved westwards into the Caucasian and European steppes, where they participated in the events of the Migration Period.