Parthia was an ancient civilization that ruled in the northeast of Persia (modern-day Iran). The Parthian empire lasted from 247 B.C. to A.D. 228 in ancient Persia (Iran). The Parthians defeated the successors to Alexander the Great, the Seleucids, and conquered most of the Middle East. It also controlled part of the Silk Road.
The Parthian empire helped revive the Achaemenid empire and stem the advances of the Roman empire. The Parthian empire occupied territory in present-day Iran, Iraq, Turkey, Armenia, Azerbaidzhan, Turkmenistan, Georgia, Palestine, Israel, Afghanistan, Tajikistan, Pakistan, Syria, Lebanon and Jordan.
The term "Parthian" (PAR-thee-un) is from an interesting characteristic of the Parthian fighters, who would fire arrows from horseback while in retreat. Thus Parthian means "relating to, being, or having the effect of a shot fired while in real or feigned retreat" (Merriam-Webster dictionary). A "Parthian shot" is a "parting shot" or criticism voiced by someone leaving.