During the Hellenistic period the importance of Greece proper within the Greek-speaking world declined sharply. The great centers of Hellenistic culture were Alexandria and Antioch, capitals of Ptolemaic Egypt and Seleucid Syria respectively. The conquests of Alexander greatly widened the horizons of the Greek world, making the endless conflicts between the cities which had marked the 5th and 4th centuries BC seem petty and unimportant. It led to a steady emigration, particularly of the young and ambitious, to the new Greek empires in the east. Many Greeks migrated to Alexandria, Antioch and the many other new Hellenistic cities founded in Alexander's wake, as far away as modern Afghanistan and Pakistan.
What particular demographic emigrated to the new Greek empires?
young and ambitious