Origins of the Persian Empire
The
speakers of Persian languages may have migrated into that part of Asia
as early as 1500 B.C. Presumably they were originally a nomadic tribe who filtered down through the
Caucasus to the plateau. 
They
apparently subjugated peoples already there and mingled with them, but
their dominance of particular areas is recorded in the place names Parsua
and Parsumash. The Assyrian rulers were by the 9th cent. B.C. sending expeditions against them, and the recurrence of those campaigns is evidence
of the strength of the early Persians.
