Which ancient dynasty helped extend the name Persia across the Iranian plateau?

The name "Persia" originated from a region in southern Iran known as Persis (or Parsa, modern Fars). The use of this name was gradually extended by the ancient Greeks and other peoples to apply to the entire Iranian plateau during the rule of the Achaemenid Empire (559–330 BCE).12

As the Achaemenids—who were natives of Persis—expanded their political sphere across the region, their dominance led outsiders to associate the name of their home territory with the broader area they governed. This naming convention was further reinforced by the subsequent Sasanian dynasty, which was also native to Persis and whose culture dominated the Iranian plateau until the 7th century CE. While the region has historically been referred to as Persia in the West, its people have traditionally called their country Iran, meaning "Land of the Aryans," a name officially adopted for international use in 1935.21