Parthian+empire

__**Why**__ is it significant? - The Romans saw the Euphrates as a frontier. They slowed down their expansion greatly.
 * Who** are the relevant people and empires? A significant political and cultural power in the Near East (no Iran)
 * What** is it? Almost a counterweight to the roman empire.
 * When** are the relevant dates and periods? In 53 BC Crassus died invading them. Lasted from 247 BC to 244 AD.
 * Where** was it? Modern day Iran.