Parthians
Definition:
The Parthian Empire existed from about 247 B.C. ? A.D. 224, after revolting against the Seleucids. It is thought that the founder was Arsaces I of the tribe of the Parni, from which, Parthians. The Empire was located in modern Iran, from the Caspian Sea to the Tigris and Euphrates Valley. The Sasanians, under Ardashir I (who ruled from A.D. 224-241), defeated the Parthians, thereby putting an end to the Parthian Empire.
Also Known As: Arsacids
Examples:
Not everyone considered the Parthians heir to the early or Achaemenid kings. The later Persian Empire, the Sassanians, considered the Parthians a feudal system of kings and so not like the Persian system, according to Forgotten Empire: The World of Ancient Persia, by John E Curtis and Nigel Tallis (2005). It wasn't until a supposed descendant of the great Darius, Ardashir, brought back the kingship that the ancient empire was restored.