From

 

my good buddy @ancientexplorers  (IG)

According to ancient historical accounts from Herodotus, the formation of the Median nation under Deioces involved six distinct tribes. As chronicled in the Histories:

Deioces united the Medes, becoming their sole ruler. The six tribes comprising the Median nation were the Busae, Paretaceni, Struchates, Arizanti, Budii, 

and Magi.

These tribes inhabited the region known as Media proper, forming a triangular area between Rhagae, Aspadana, and Ecbatana-present-day Iran, spanning between Tehran, Isfahan, and Hamadan. The Magi, a sacred caste ministering to the Medes' spiritual needs, resided in Rhagae (modern Tehran). The Paretaceni tribe occupied the vicinity of Aspadana (modern Isfahan), while the Arizanti settled in and around Kashan (Isfahan Province). The Busae tribe called the region around the future Median capital of Ecbatana home, near modern Hamadan. Villages within the Median triangle housed the Struchates and the Budii. 

Yeah...they came from the east.

They saw the star.

They were Zoroastrians.

They knew what was up.