Calling themselves the Parsa after their original Aryan tribal name Parsua, Persians had settled in a land which they named Parsua, bounded on the west by the Tigris River and on the south by the Persian Gulf.

This became their heartland for the duration of the Achaemenid Empire.

It is from this region that eventually Cyrus the Great (Cyrus II of Persia) will advance to defeat the Median, the Lydian, and the Babylonian Empires, opening the way for subsequent conquests into Egypt and Asia minor.