As far as I know there was no ..."pension" (lol) empire that any greek leader conquered. In case you meant Persian Empire, it was Alexander the Great who conquered it.
Alexander The Great
Alexander, king of Macedonia, conquered the Persian Empire and took it over. The empire stretched from Libya-Egypt through the Middle East to Central Asia and today's Pakistan. He was also Hegemon (leader) of mainland Greece.
Well, seeing as how this question is filled under Alexander the Great, I would assume that you should know that the leader of Macedonia, Alexander the Great, defeated the Persian empire and held the title and office of the king of Persians.
Egypt was conquered by Cambyses II, the ruler of the Achaemenid Empire, the second of the four pre-Islamic Persian Empires
Early on - in Macedonia. For the last ten years (he died at 32) it was in Africa and Asia conducting his conquest of the Persian Empire, from Asia Minor to Egypt to Persia, to Central Asia and India.
the leader of Persia was ahmadi nejad
First King Agesilaus I of Sparta, but he was recalledto deal with troubles in Greece. Then King Philip II of Macedonia, but he was assassinated before he could get his invasion going. Then his son Alexander III (the Great) who successfully took over the Persian Empire.
Cyrus
Cyrus, leader of the Persian empire
Cyrus the Great.
Cyrus the Great.