[155-138 B.C.]
On his way back from India Eucratides was murdered by his son and co-regent, probably Heliocles [ca. 155 B.C.]. The date of this murder may be fixed by that of Demetrius, who must have been born not later than 224 B.C., and may be taken to have lost his kingdom not later than 159 B.C. Eucratides cannot, according to Justin’s account, have lived many years longer.
In the midst of the civil wars, which became more serious after the death of Eucratides, Mithridates of Parthia began to extend his dominions at the expense of Bactria: even in the life-time of Eucratides he succeeded in annexing two satrapies. Another account makes Mithridates rule as far as India, and declares him to have obtained without war the old kingdom of Porus, or the rule over all nations between the Indus and the Hydaspes. The two accounts are reconciled by Chinese records, which tell that, about 161 B.C., the nomad people Sse broke into the valley of the Cophen and founded a kingdom in the very place of the Parthian conquests in India, which must therefore have been ephemeral. This fact has its importance, as illustrating the way in which the internal wars of the east Iranian Greeks helped to prepare the ground for the Scythian invasion. After this success in the east Mithridates turned his attention to the west, where the chances of success were not less inviting. Demetrius had at length fallen before a coalition of the neighbouring sovereigns, powerfully supported by the Romans through their instrument, the exile Heraclides. A pretender, Alexander, in 145 B.C., was utterly defeated by Ptolemy, and slain in his flight by an Arab chieftain. Demetrius (II) Nicator, however, soon made himself bitterly hated, and five years of fighting drove him out of the greater part of Syria.
MEDIA AND BABYLONIA CONQUERED
Such was the state of the empire when war broke out between Media and Parthia, which was finally decided in favour of the latter. The short-lived independence of Media was soon cut short by Mithridates, who did not lose the opportunity afforded by the civil wars of Syria in 147 B.C. Babylonia followed the fate of Media; and the whole province, with its capital Seleucia, fell into the hands of the Parthians. Thus the East was finally lost to the Macedonians.
The change of rule was not well received by the new subjects of Parthia, least of all by the Greeks and Macedonians of the upper provinces, who sent embassy after embassy to Demetrius. In 140 B.C. he marched into Mesopotamia, and thence by Babylon to the upper provinces. He was well received by the natives, and even the small native states made common cause with him against the proud barbarians, whose neighbourhood they felt to be oppressive. He was joined by the Persians and Elymæans, and the Bactrians helped him by a diversion, appearing now for the first time as an independent people. At first things went well, and the Parthians were defeated in several battles, but in Media in 139 B.C. Demetrius was surprised by the lieutenant of Mithridates during negotiations for peace; his forces were annihilated, and he himself was taken prisoner and dragged in chains through the provinces that had joined his cause. The Parthian king received his captive with favour and assigned him a residence and suitable establishment in Hyrcania. He even gave him his daughter Rhodogune, and promised to restore him to his kingdom, but this plan was interrupted by death.
[138 B.C.]
Mithridates’ latest campaign was against the king of Elymais; the rich temples yielding him a booty of ten thousand talents (£2,258,000 or $11,290,000). The country was brought under Parthia, but continued to have its own kings. The coins make it likely that Mithridates simply set up a new dynasty, a branch of his own house. Mithridates died at a good old age in 138 B.C., or a little later. His memory was reverenced almost equally with that of the founder of his house, but his real glory was much greater, for it was he who made Parthia a great power. He is praised as a just and humane ruler, who, having become lord of all the lands from the Indian Caucasus to the Euphrates, introduced among the Parthians the best institutions of each country, and so became the legislator of his nation.
PARTHIAN “KINGDOMS”
The divisions of the empire which he founded can be sketched by the aid of an excerpt from the itinerary of Isidore of Charax (at the beginning of the Christian era) and from Pliny. The empire was divided into the upper and lower kingdoms, separated by the Caspian Gates. The lower kingdoms were seven: (1) Mesopotamia and Babylonia, (2) Apolloniatis, (3) Chalonitis, (4) Carina, (5) Cambadene, (6) Upper Media, (7) Lower or Rhagian Media. The upper kingdoms were eleven: (8) Choarene, (9) Comisene, (10) Hyrcania, (11) Astauene, (12) Parthyene, (13) Apauarcticene, (14) Margiana, a part of Bactria, (15) Aria, (16) the country of the Anauans, (17) Zarangiana, and (18) Arachosia, now called “White India.” The eighteen Parthian kingdoms thus correspond to six old satrapies. The Parthians gave much less attention to the west than did their predecessors, and they still left Mesopotamia as the only great satrapy. We note also that they cared little for reaching the sea, which they can have touched only for a little way at the mouth of the Euphrates; and even here they allowed the petty Characene quite to outstrip them in competing for the great sea trade.