Four years, fourteen kings: How internal chaos dismantled the mighty Sasanian Empire
Following a devastating defeat by Byzantium, the Sasanian Empire collapsed into a brutal four-year civil war. As noble factions vied for control, the throne became a revolving door for fourteen different rulers. This rapid instability fractured the state, leaving it defenseless against the rising tide of the Arab conquests.
The Sasanian civil war, or Interregnum, ignited in 628 after a palace coup deposed King of Kings Khosrow II. Orchestrated by a coalition of feudal families, the coup replaced him with his son, Kavad II. To consolidate his precarious rule, Kavad executed his brothers and father, yet his reign lasted only months before he succumbed to a plague in September 628. This set a pattern of terminal instability, with power shifting from the monarchy to competing noble factions, specifically the Parthian Pahlav, the Persian Parsig, the Nimruzi, and the faction led by general Shahrbaraz.
The conflict was defined by a rapid turnover of monarchs, including the child Ardashir III, the usurper Shahrbaraz, and the daughters of Khosrow II, Boran and Azarmidokht. Noble leaders like Farrukh Hormizd and Rostam Farrokhzad acted as kingmakers, often minting their own coins and asserting autonomy. The violence was relentless; rulers were frequently murdered or blinded, and the central authority disintegrated as provincial governors in regions like Yemen and Mazun declared independence. By the time Yazdegerd III was installed in 632 to end the hostilities, the empire was a shell of its former self.
The consequences were catastrophic. The internal fighting decimated the Sasanian army and exhausted the treasury, leaving the empire vulnerable to external threats from Göktürks and Khazars. More critically, the disintegration of central control coincided with the rapid expansion of Islam across the Arabian Peninsula. The Sasanian state, which had once rivaled Byzantium, found itself unable to mount a unified defense. The chaos concluded with the empire's final collapse during the Arab invasions, culminating in the death of Yazdegerd III in 651, an event many contemporaries viewed as the inevitable result of the nation's internal decay.
Source: Sasanian civil war of 628–632
