In the 7th century BC, Media's tribes came together to form the Median Kingdom, which remained a Neo-Assyrian vassal. Between 616 and 609 BC, King Cyaxares (624–585 BC), allied with King Nabopolassar of the Neo-Babylonian Empire against the Neo-Assyrian Empire, after which the Median Empire stretched across the Iranian Plateau as far as Anatolia. Its precise geographical extent remains unknown.
A few archaeological sites (discovered in the "Median triangle" in western Iran) and textual sources (from contemporary Assyrians and also ancient Greeks in later centuries) provide a brief documentation of the history and culture of the Median state. Apart from a few personal names, the language of the Medes is unknown. The Medes had an ancient Iranian religion (a form of pre-Zoroastrian Mazdaism or Mithra worshipping) with a priesthood named as "Magi". Later during the reigns of the last Median kings, the reforms of Zoroaster spread into western Iran.
Thus Deioces collected the Medes into a nation, and ruled over them alone. Now these are the tribes of which they consist: the Busae, the Paretaceni, the Struchates, the Arizanti, the Budii, and the Magi.
The six Median tribes resided in Media proper, the triangular area between Rhagae, Aspadana and Ecbatana. In present-day Iran, that is the area between Tehran, Isfahan and Hamadan, respectively. Of the Median tribes, the Magi resided in Rhaga, modern Tehran. They were of a sacred caste which ministered to the spiritual needs of the Medes. The Paretaceni tribe resided in and around Aspadana, modern Isfahan, the Arizanti lived in and around Kashan (Isfahan Province), and the Busae tribe lived in and around the future Median capital of Ecbatana, near modern Hamadan. The Struchates and the Budii lived in villages in the Median triangle.