In the late 5th century AD the Sassanians had to deal with the threat of the Huns (Hephthalites) on their eastern border. The Sassanian king Firoz was captured by them and was forced to pay a ransom for his own release. He also gave to the Huns Kavadh, his son, who in AD 488 was installed on the throne of Iran with their aid.
Probably because he himself was opposed to the nobility and anxious to curb their power, King Kavadh supported the revolutionary movement of Mazdakism which preached social equality and threatened the privileges enjoyed by the Sassanian nobility.
The Mazdakite revolution caused widespread disruption to the established Sassanian fiscal and legal systems and the Mazdakites were fiercely opposed by the nobility and the orthodox Zoroastrian clergy. Unable to cope with the situation, Kavadh fled into exile with the Huns.
His son Khusrau I (AD 531-578), who has already caused Mazdakites to be massacred in AD 528, succeeded his father as king and crushed the Mazdakites. He did, however, recognize the serious inadequacies in the way property and income were assessed for taxation and he therefore introduced reforms.
In addition he encouraged the development of a lesser nobility, responsible for local administration and answerable to the king. Although power and riches initially remained in the hands of an elite few, they were gradually counterbalanced by these lesser nobles.
