I have included only a few items concerning the history of this empire. A good source for more details can be
found on Wikipedia or in history books.
In 247 BC, leader of the Parni tribe, Arsaces I, seceded
from the Seleucid Empire and formed
the Parthian Empire. An important revenue generator was the Silk Road,
which ran through its northern region. An early ally was the Greco-Bactrian
Expansion beyond the Gates of Alexander started under Phraates I.
Mithridate I expanded territory by conquering
Media and Mesopotamia.
His forces also reached the Indus River. In the 1st century BC,
Parthia allied with the Indo-Parthian Kingdom.
Parthia's eastern border was stabilized between 30 and 375 AD, during existence of the
Kushan Empire. This left Parthia free to combat
Roman expansion. The two empires fought numerous wars
and Rome suffered one of its worst defeats at Carrhae in 53 BC.
Parthian Crown Prince, Pacorus I, raided as far west as Antioch.
In 20 BC, Phraates IV signed a peace treaty with Augustus Caesar,
who gave an Italian slave girl as a gift. The girl later became Musa,
Queen of Parthia. She eventually was forced into exile after marrying her son.
Another Parthian-Roman war (58-63 AD) broke out after Vologeses I
invaded the Roman client kingdom of Armenia. Roman emperor
Trajan seized Mesopotamia in 116 AD. However, he withdrew the
following year after Babylon revolted.
A planned return in 118 AD failed upon Trajan's death in 117 AD. During another Parthian-Roman war
(161-166 AD), Roman forces razed Ctesiphon and
captured Seleucia. It was a hollow victory, as Roman
troops contracted a deadly disease (probably smallpox) that later ravaged Roman domains. Wars with Rome
weakened Parthia, which was followed by the Sassanid Empire.