45
FROM THE PERSIAN EMPIRE TO THE SASSANIANS
in Rome, the name Arsaces was used as a title by the fi rst 19 kings of
Parthia, the majority of whom retained their personal names, and the
dynasty is referred to as the Arsacid. Arsaces II made a treaty with the
satrap of the neighboring and still rebellious province of Bactria, allow-
ing him to consolidate his authority and pursue expansion.
Parthian expansion was at the expense of the Seleucid Empire, as
Arsaces II and the next three of his successors methodically picked
off territory from the eastern satrapies. However, they were unable to
defeat Seleucid power outright, especially during the reign of Antiochus
the Great. During this period, Parthia was an autonomous state within
the Seleucid Empire. It was the sixth Parthian king whom historians
have credited with creating the Parthian Empire. Arsaces VI Mithridates
(also known as Mithridates I and Mithridates the Great, r. ca. 171–138
B.C.E.), the younger brother of his predecessor, Arsaces V Phraates, came
to power at a conspicuous time in history as “one by one the provinces
of Iran were lost to the Seleucids, and became a series of independent
monarchies” (Colledge 1967, 28). Nevertheless, Mithridates bode his
time for almost 11 years. In 160
B.C.E., the Parthians overran Tapiura
and Traxiane to the east, formerly Bactrian territory. He then turned
westward, and by 147
B.C.E., the Parthians occupied the ever-rebellious
kingdom of Media. A few years later, Mithridates took a step that sig-
naled Parthian independence from Seleucid rule: He became the fi rst
Parthian king to issue coinage.
The record next becomes somewhat hazy, but Mithridates returned
east, “perhaps on account of an attack on his borders” (Colledge 1967,
29). After further eastern conquest, he turned westward again with the
intention of taking Babylonia as well as a few kingdoms, such as Elam
and Armenia. This he swiftly accomplished, in 141
B.C.E., but once
again had to repel an invasion in the east—this time from Bactria. The
Seleucid king, Demetrius II, took advantage of Mithridates’ preoccupa-
tion in the east to mount a counterattack to regain his lost territory.
But Mithridates defeated the Bactrians, turned west for the third time,
and defeated Demetrius, taking the Seleucid king prisoner. Demetrius
thereupon forsook his throne but reclaimed it ca. 129
B.C.E. and held it
for another four years after that. Nevertheless, the Seleucid Empire was
at a virtual end; the dynasty continued to rule until 64
B.C.E. but had
long since fallen back on Syria as its fi nal domain, where it served as a
buffer state between the Parthian and the Roman Empires. Mithridates
died in 138
B.C.E., but the empire he founded continued to expand.
By 113
B.C.E., during the reign of Arsaces XI Mithridates (c. 124–87
B.C.E.), upper Mesopotamia fell under Parthian sovereignty. This was