How did the ancient region of Persis give rise to the name Persia?

The name Persia originated from the ancient region of Persis—also known as Pārs or Parsa—located in southwestern Iran and roughly corresponding to the modern province of Fārs.123

The region derived its name from the Parsua (or Parsa), an Indo-European nomadic tribe that settled in the area around the 7th century BCE. During the rise of the Achaemenid Empire (559–330 BCE), the Achaemenid rulers, who were natives of Persis, expanded their political influence across the Iranian plateau.124

As the ancient Greeks encountered these Achaemenid inhabitants, they began using the term "Persia" to describe the people and the region. This designation was gradually extended by the Greeks and other foreign powers to encompass the entire Iranian plateau. The association was further solidified by the later Sasanian dynasty, which was also native to Persis and dominated the region until the 7th century CE. While the local population has traditionally referred to their land as Iran, the name Persia remained the standard Western term until the government officially requested the use of "Iran" in 1935.23