Parthian Empire

The Parthian Empire (/ˈpɑːrθiən/), also known as the Arsacid Empire (/ˈɑːrsəsɪd/), was a major Iranian political and cultural power centered in ancient Iran from 247 BC to 224 AD. Its latter name comes from its founder, Arsaces I, who led the Parni tribe in conquering the region of Parthia in Iran's northeast, then a satrapy (province) under Andragoras, who was rebelling against the Seleucid Empire. Mithridates I (r. c. 171 – 132 BC) greatly expanded the empire by seizing Media and Mesopotamia from the Seleucids. At its height, the Parthian Empire stretched from the northern reaches of the Euphrates, in what is now central-eastern Turkey, to present-day Afghanistan and western Pakistan. The empire, located on the Silk Road trade route between the Roman Empire in the Mediterranean Basin and the Han dynasty of China, became a center of trade and commerce.

The Parthians largely adopted the art, architecture, religious beliefs, and regalia of their culturally heterogeneous empire, which encompassed Persian, Hellenistic, and regional cultures. For about the first half of its existence, the Arsacid court adopted elements of Greek culture, though it eventually saw a gradual revival of Iranian traditions. The Arsacid rulers were titled "King of Kings", claiming inheritance of the Achaemenid Empire; indeed, they accepted many local kings as vassals, although the Achaemenids would have had centrally appointed, albeit largely autonomous, satraps. The court did appoint a small number of satraps, largely outside Iran, but these satrapies were smaller and less powerful than the Achaemenid potentates. With the expansion of Arsacid power, the seat of central government shifted from Nisa to Ctesiphon along the Tigris (south of Baghdad), although several other sites also served as capitals.

The earliest enemies of the Parthians were the Seleucids in the west and the Scythians in the north. However, as Parthia expanded westward, they came into conflict with the Kingdom of Armenia, and eventually the late Roman Republic. Rome and Parthia competed with each other to establish the kings of Armenia as their tributaries. The Parthians destroyed the army of Marcus Licinius Crassus at the Battle of Carrhae in 53 BC, and in 40–39 BC, Parthian forces captured the whole of the Levant except Tyre from the Romans; Mark Antony led a Roman counterattack. Several Roman emperors invaded Mesopotamia in the Roman–Parthian Wars of the next few centuries, capturing the cities of Seleucia and Ctesiphon. Frequent civil wars between Parthian contenders to the throne proved more dangerous to the Empire's stability than foreign invasion, and Parthian power evaporated when Ardashir I, ruler of Istakhr in Persis, revolted against the Arsacids and killed their last ruler, Artabanus IV, in 224 AD. Ardashir established the Sasanian Empire, which ruled Iran and much of the Near East until the Muslim conquests of the 7th century AD, although the Arsacid dynasty lived on through branches of the family that ruled Armenia, Caucasian Iberia, and Caucasian Albania.

Native Parthian sources, written in Parthian, Greek and other languages, are scarce when compared to Sasanian and even earlier Achaemenid sources. Aside from scattered cuneiform tablets, fragmentary ostraca, rock inscriptions, drachma coins, and the chance survival of some parchment documents, much of Parthian history is only known through external sources. These include mainly Greek and Roman histories, but also Chinese histories, prompted by the Han Chinese desire to form alliances against the Xiongnu. Parthian artwork is a means of understanding aspects of society and culture that are otherwise absent in textual sources.

Before Arsaces I founded the Arsacid dynasty, he was chieftain of the Parni, an ancient Central Asian tribe of Iranian peoples and one of several nomadic tribes within the confederation of the Dahae. The Parni most likely spoke an eastern Iranian language, in contrast to the northwestern Iranian language spoken at the time in Parthia. The latter was a northeastern province, first under the Achaemenid Empire, and then the Seleucid Empire. After conquering the region, the Parni adopted Parthian as the official court language, speaking it alongside Middle Persian, Aramaic, Greek, Babylonian, Sogdian and other languages in the multilingual territories they would conquer.

Why the Arsacid court retroactively chose 247 BC as the first year of the Arsacid era is uncertain. A. D. H. Bivar concludes that this was the year the Seleucids lost control of Parthia to Andragoras, the appointed satrap who rebelled against them. Hence, Arsaces I "backdated his regnal years" to the moment when Seleucid control over Parthia ceased. However, Vesta Sarkhosh Curtis asserts that this was simply the year Arsaces was made chief of the Parni tribe. Homa Katouzian and Gene Ralph Garthwaite claim it was the year Arsaces conquered Parthia and expelled the Seleucid authorities, yet Curtis and Maria Brosius state that Andragoras was not overthrown by the Arsacids until 238 BC.

It is unclear who immediately succeeded Arsaces I. Bivar and Katouzian affirm that it was his brother Tiridates I of Parthia, who in turn was succeeded by his son Arsaces II of Parthia in 211 BC. Yet Curtis and Brosius state that Arsaces II was the immediate successor of Arsaces I, with Curtis claiming the succession took place in 211 BC, and Brosius in 217 BC. Bivar insists that 138 BC, the last regnal year of Mithridates I, is "the first precisely established regnal date of Parthian history." Due to these and other discrepancies, Bivar outlines two distinct royal chronologies accepted by historians. A fictitious claim was later made from the 2nd-century BC onwards by the Parthians, which represented them as descendants of the Achaemenid king of kings, Artaxerxes II of Persia (r. 404 – 358 BC).

For a time, Arsaces I consolidated his position in Parthia and Hyrcania by taking advantage of the invasion of Seleucid territory in the west by Ptolemy III Euergetes (r. 246–222 BC) of Egypt. This conflict with Ptolemy, the Third Syrian War (246–241 BC), also allowed Diodotus I to rebel and form the Greco-Bactrian Kingdom in Central Asia. The latter's successor, Diodotus II, formed an alliance with Arsaces I against the Seleucids, but Arsaces was temporarily driven from Parthia by the forces of Seleucus II Callinicus (r. 246 – 225 BC). After spending some time in exile among the nomadic Apasiacae tribe, Arsaces I led a counterattack and recaptured Parthia. Seleucus II's successor, Antiochus III the Great (r. 222 – 187 BC), was unable to immediately retaliate because his troops were engaged in putting down the rebellion of Molon in Media.