Between 334 and 330 bc Alexander completed the conquest of the whole Achaemenian Empire. (For the story of the conquest, see Alexander the Great and ancient Greek civilization: Alexander the Great.) Alexander’s burning of the royal palace at Persepolis in 330 symbolized the passing of the old order and the introduction of Greek civilization into western Asia. Greek and Macedonian soldiers settled in large numbers in Mesopotamia and Iran. Alexander encouraged intermarriage and fostered Greek culture, but he also retained a large part of the Achaemenian administrative structure and introduced Oriental elements and Greek political institutions.
Alexander left no heir. His death in 323 bc signaled the beginning of a period of prolonged internecine warfare among the Macedonian generals for control of his enormous empire. By the end of the 4th century bc, Seleucus I Nicator had consolidated his control over that part of Alexander’s territory that had corresponded to the Achaemenian Empire. Seleucus—who, with his son Antiochus I Soter, assumed supreme power—established a government with two capitals: Antioch on the Orontes River in Syria and Seleucia on the Tigris River in Babylonia. The greatest part of western Asia—from the Aegean to the Punjab—belonged to this vast Seleucid kingdom, and to its diverse and varied populace must be added several allied Greek cities, both in Greece and in Asia Minor. (See also bc to c. ad 620" class="md-crosslink">Mesopotamia, history of: Mesopotamia from c. 320 bc to c. ad 620.) The nobles and the nomads
As he was finishing the conquest of eastern Iran—and at a moment when his attention was being drawn toward the conquest of India—Alexander was confronted by two human factors that were of the greatest importance for the future of his empire. The first of these was the powerful local aristocracy of this part of the Achaemenian Empire, which held enormous properties and dominated the indigenous population. The second was the nomad population that for centuries had wandered along the northern and northeastern frontiers of Iran.
Alexander seems to have admired greatly the barons of eastern Iran; he had taken note of their ardour during the two years of hard and constant fighting in his conquest of northeastern Iran. Realizing how such a force could benefit the future of his empire, Alexander convoked an assembly of Bactrian nobles. He ordered 30,000 young men to be chosen for training in the Macedonian military disciplines. He understood the importance and effectiveness of the Iranian light cavalry armed with the bow, and his army would make use of this training in its march toward the plains of India. Alexander married Roxana of Sogdiana, daughter of a chief of one of the conquered countries, thereby symbolizing the union of the two peoples.
But Alexander was not unaware that other measures were needed to ensure his control of these vast territories. He founded many new cities, or refounded some that were already in existence. Many of these were placed strategically along the northern frontiers as protection. Almost half of these new cities were located in the high (eastern) satrapies. This policy of Alexander’s would soon be abandoned by the Seleucids, whose efforts at city planning were mostly confined to their western possessions. In contrast with Alexander, the Seleucids were unable to maintain the good rapport with the eastern Iranian nobility that Alexander had believed essential. And this deficiency, a result of the Seleucids’ “pro-Macedonian” policies, was one of the principal causes for the progressive decline of the Seleucid empire.
The second of the human factors, the nomads, inhabited the immense territories beyond the northern frontiers. They fought constantly with the settled populations but could nevertheless occasionally ally with them in the face of necessity. When Alexander arrived on the banks of the Jaxartes (Syr Darya) River, it marked the limit of the “civilized” world; beyond stretched the Eurasian wilderness. The Roman historian Quintus Curtius recounts Alexander’s meeting with a delegation of Scythians who gave him a warning. They told him,
Just cross the Tanais [properly the Jaxartes] and you will see how far Scythia stretches. You will never conquer the Scythians. Our poverty makes us quicker than your army, which bears plunder from so many nations. Just when you think we are far away, then will you see us in your camp. We know how to pursue and how to flee with the same swiftness. [One recalls here the famous “Parthian shot,” a metaphor drawn from a neighbouring people.] We seek out those deserts totally devoid of human culture rather than the cities and the rich countryside.
These words sum up what the nomad world represented to an empire that stretched several thousand miles from east to west. The settled population knew the threat only too well. Alexander was not the first to cross swords with the nomads. Cyrus II, founder of the Achaemenian Empire, had paid with his life while fighting them, and Darius I, believing he could take them from behind through southern Russia, suffered a crushing defeat in his campaign against the Scythians along the shores of the Black Sea.
If the nomads and the eastern Iranian nobility were the two dominant factors in the decline of the Seleucid kingdom and if the events they provoked were some of the principal causes for the exhaustion and eventual fall of that state, these same causes later played a significant role in the collapse of Parthian power. Parthia was undermined by an aristocracy that retained its military power and refused to bend before the royal will or to give up its meddling in the country’s politics. In the meantime the kingdom’s unruly nomadic neighbours to the north and the northeast, at the cost of the lives of several Parthian sovereigns, weakened the kingdom and sometimes added a complementary element to the often numerous intrigues of the pretenders to supreme power during the course of the almost half a millennium of the existence of the Parthian kingdom. The Seleucids
In the struggle for power after Alexander’s death, Seleucus I brought under his control the whole eastern part of Alexander’s empire. But even before he had consolidated his control over this territory, the eastern provinces on the Indian frontier had begun to revolt. By about 304 bc Seleucus was forced to abandon these to Chandragupta, the founder of the great Maurya empire in India. This was a serious loss to the Seleucids, for they lost not only the Indian territory conquered by Alexander but also frontier districts west of the Indus River. As recompense, Seleucus received 500 elephants, which he took back with him to Syria. From this time on, the west was dominant in the Seleucids’ politics, to the detriment of their eastern possessions. This near disinterest of the Seleucids in the far-off eastern regions must have alienated the Greeks who had settled there, far from their homeland, and the thought of taking back their full independence could not have been far from their minds.
Soon afterward (c. 290–280 bc) the two eastern provinces of Margiana and Aria suffered an invasion by nomads. But the invasion was repelled, and the nomads were pushed back beyond the Jaxartes. Demodamas, a general to the first two Seleucid kings, crossed the river and even put up altars to Apollo, ancestor of the dynasty. Alexandria in Margiana and Heraclea in Aria, founded by Alexander, were rebuilt by Antiochus I under the names Antioch and Achaea, respectively, and a wall nearly 100 miles (160 km) long was put up to protect the oasis of Merv against future invasions, the menace of which was never far away. Patrocles received a commission to explore the Caspian Sea.
Seleucus I and his successors hoped to Hellenize Asia and held the conviction that the Greeks and Macedonians were a superior people and the bearers of a superior civilization. A network of cities and military colonies was built to assure the stability of a state whose inhabitants would be Asians. The Greek language made deep inroads, especially among the families of those numerous Greeks who married the local women and among those engaged in commerce. But after the 2nd century bc and the slowing of the Greco-Macedonian immigration, the Greek language lost ground and the local element became dominant.