Until 1935. I wrote a paper suggesting that actually the Assyrian empire was what formed the Persian empire. Had a decent debate with a Cambridge don after the paper was critiqued.
I really enjoyed my classics work.
Basically yes...the current Iran is a fraction of the empire that covered most of North Africa to India and southern Russia through the caucuses.
It was really the first of the worlds empires..then came Greek/ Roman/ and the European empires