Peroz I was the Sasanian King of Kings of Iran from 459 to 484. A son of Yazdegerd II, he disputed the rule of his elder brother and incumbent king Hormizd III, eventually seizing the throne after a two-year struggle. His reign was marked by war and famine. Early in his reign, he successfully quelled a rebellion in Caucasian Albania in the west, and put an end to the Kidarites in the east, briefly expanding Sasanian rule into Tokharistan, where he issued gold coins with his likeness at Balkh. Simultaneously, Iran was suffering from a seven-year famine. He soon clashed with the former subjects of the Kidarites, the Hephthalites, who possibly had previously helped him to gain his throne. He was defeated and captured twice by the Hephthalites and lost his recently acquired possessions.

The Sasanian Empire or Sassanid Empire, officially known as Eranshahr, was the last Iranian empire before the early Muslim conquests of the 7th to 8th centuries. Named after the House of Sasan, it endured for over four centuries, from 224 to 651, making it the second longest-lived Persian imperial dynasty after the Arsacids of the Parthian Empire.