Egyptians, Greeks, a wide range of Semitic peoples, and other Indo-Europeans and Asiatics.
Which empire?
The Persians were not seafarers, and relied on other ethnics within their empire to provide their navy and trading fleet. The Greeks within their empire in Asia Minor and the Islands provided a significant part of this shipping and fighters which supported Persian security and prosperity.
The Golden Age of Athens, where it turned the Delian League which it had led against the Persian Empire into an empire of its own and lived the golden life on the proceeds of that empire.
It lasted from 550 to 331 BCE - over two centuries.
The Persian Empire.
The Persian Empire was not a person.
All dead. They lived and died over two thousand years ago.
Persian Empire
The Persian Empire absorbed the Babylonian Empire.
Alexander the Great defeated the Persian empire
The Persian Empire absorbed the Baabylonian Empire.
After peace was made, Athens converted the Delian League it had led against the Persian Empire into an empire of its own and lived high on the hog from the proceeds it extorted from those Greek city-states.