So you only consider the land of the Medes and Persians to be ancient Iran? Yes. That's ancient Iran were the Achameanid Dynasty came from... and were after all talking about Achameanid Persia. There were proto-Iranian people in what is today Iran before (Elamites in Southern Iran) but that's not the Persians we are dealing with. The giant Persian Empire had Iran at it's core, but as you know consisted of the conquered countries.
And according to the Darius Behishtun...
Column 1:
(1.1-3.) I am Darius the Great King, King of Kings,King in Persia, King of countries, son of Hystaspes, grandson of Arsames, an Achaemenian.
(1.3-6.) Darius the King says: My father was Hystaspes; Hystaspes' father was Arsames; Arsames' father was Ariaramnes; Ariaramnes' father was Teispes;
Teispes' father was Achaemenes.
(1.6-8.) Darius the King says:
For this reason we are called Achaemenians. From long ago we have been noble. From long ago our family had been kings.
(1.8-11.) Darius the King says: there were 8 of our family who were kings before me; I am the ninth; 9 in succession we have been kings.
...Achaemenes was the first "king" of "Persia", right?
(Just getting on track here so bear with me.)