What follows is a brief sketch of the history of the ancient Persian Empire, in which the present Iran has its roots. Early in the first millenium BC, major invasions of Indo- European tribes took place. They gave their name for themselves to their new homeland they were Aryans, meaning "of noble origin", and from this the name Iran is derived. According to some sources, the speakers of Iranian languages may have migrated into this part of southwest Asia as early as 1,500 BC. They apparently managed to subjugate peoples already living there and mingle with them, but their dominance of particular areas is recorded in the derived place names of Parsua and Parsumash. The Assyrian rulers were by the 9th century BC sending expeditions against them, and the resources of those campaigns are evidences of the Early Persians.