As Greek I have to select in the only one that unite for first time the Greeks.So my favour is the Macedonian Empire or better the Hellenstic Empire (s).

 

While the clasical age of Greece produced great literature, poetry, philosophy, drama, and art, the Hellenistic age "hellenized" the world. At the root of Hellenism were the conquests of Philip II and his son, Alexander III. However, the Macedonians did more than control territory.they actively exported Greek culture: politics, law,liteerature, philosophy, religion and art. This was a new idea, exporting culture, and more than anything else this exporting of culture would deeply influence all the civilizations and cultures that would later erupt from this soil: the Romans, the Christians, the Jewish diaspora, and Islam.

Macedonia all during the age of the Hellenic city-states was an anomaly.It was a typical  Hellenic Archaic (not classical) kingdom.  Macedonians were the Greeks who had to contend, then, with all the European tribes, many of which were war-like. So the Macedonians served as a kind of buffer for the Greeks, as the faithful Greeks who stood between the tribal Europeans and the Greek city-states. For all that, the Macedonians were deeply unappreciated by their fellow Greeks; they were looked on as no better than barbarians themselves, particularly since they had never developed or adopted the Greek polis and education.

Macedonians were ruled by a king, much like the Mycenean kings. The king came to power through inheritance, but first had to be approved by the army. Beneath the king was an aristocracy of nobles who had a limited amount of power; like all monarchies that shared power with an aristocracy, the balance of power frequently shifted from the king to the nobles and back again. Into this situation, at the peak of the political chaos roiling the Greek world to the south, stepped a powerful king who unified the country of Macedon and set his sights on conquering the whole of the Greek world: Philip of Macedon.

Despite the constant conflict, the Hellenistic world was an incredibly prosperous one. Alexander and his successors had liberated an immense amount of wealth from the Persian empire, and with this new wealth in circulation the standard of living rose dramatically. Each of the empires embarked on building projects, on scholarship, on patronage of the arts, and on literature and philosophy. The Ptolemies built an enormous library in their capital city of Alexandria, and sponsored the translation of a host of religious and literary works into Greek.

In my opinion this period really marked the first international culture in western, middle eastern, and north African history.

Greeks imported their culture: political theory, philosophy, art, and literature all over the known civilized world. This culture would greatly alter the culture and religion of the Mediterannean. But the flow of culture worked in the opposite direction as well; non-Greek ideas and non-Greeks flowed into Greece (and Italy). They took with them their religions, their philosophies, science, and culture; in this environment, eastern religions in particular began to take hold in the Greek city-states both in the east and in Greece. Among these religions was Zoroastrianism and Mithraism; in later years, this international environment would provide the means for the spread of another eastern religion, Christianity.


This process of the "hellenization" ("making Greek") of the world took place largely in the urban centers the Greeks began to zealously build. While the Greeks had for a long time believed that monarchy was a sign of barbarity, they had to come to terms with the reality of their new form of government. So they compromised. While they accepted the monarchy, the set about building somewhat independent poleis that had the structure of the polis without its political independence. The growth of these cities provoked massive migrations from the Greek mainland, as Greeks settled in these new, far-flung poleis to assume lucrative positions in the military and administration.

Spread  from Greece to Egypt and East India, Greek culture was the most significant of its times. The mighty empires (Droysen gave one name in this) of the Greeks hung onto this vast amount of territory for almost three centuries. Slowly, however, a new power was rising in the west, steadily building its own, accidental empire.