Sasanian civil war of 628–632

Early phase of the civil war

During the reign of Ardashir III, Mah-Adhur Gushnasp was appointed as his minister, and administered the empire greatly. One year later, Shahrbaraz with a force of 6,000 men, marched towards Ctesiphon and besieged the city. Shahrbaraz, however, was unable to capture the city, and then made an alliance with Piruz Khosrow, the leader of the Parsig faction, and the previous minister of the Empire during the reign of Ardashir's father, Kavad II. He also made an alliance with Namdar Gushnasp, the spahbed of Nimruz. Shahrbaraz, with the aid of these two powerful figures, captured Ctesiphon, and executed Ardashir III, along with Mah-Adhur himself, including other Sasanian nobles like Ardabīl. Forty days later, Shahrbaraz was murdered by Farrukh Hormizd, who then made Boran, the daughter of Khosrow II, ascend the throne. She then appointed Farrukh as the minister of the empire.

Boran was deposed by Shapur-i Shahrvaraz, the son of Khosrow II's sister Mirhran, and the Sasanian usurper Shahrbaraz. He was shortly thereafter deposed by Piruz and his faction, who did not acknowledge his rule. Piruz crowned Azarmidokht, the sister of Boran, as monarch of Iran.

Late phase of the civil war

Azarmidokht, under the advice of the nobles, recalled Farrukhzad from his arrest and invited him to serve the Sasanians in high office once again. Farrukhzad, however, declined the invitation and refused to serve under a woman. He then retired to a fire-temple in Istakhr. Farrukh Hormizd, in order to strengthen his authority and create a modus vivendi between the Pahlav and Parsig, asked Azarmidokht (who was a Parsig nominee) to marry him. Azarmidokht, however, declined. After having his proposal declined, Farrukh Hormizd "no longer shied away from the throne itself", declaring "Today I am the leader of the people and the pillar of the country of Iran." He started minting coins in the same fashion as a monarch, notably in Istakhr in Pars and Nahavand in Media. In order to deal with Farrukh Hormizd, Azarmidokht supposedly allied herself with Mihranid dynast Siyavakhsh, who was the grandson of Bahram Chobin, the famous military commander (spahbed) and briefly shah of Iran. With Siyavakhsh's aid, Azarmidokht had Farrukh Hormizd killed. Farrukh Hormizd's son Rostam Farrokhzad, who was at that time stationed in Khorasan, succeeded him as the leader of the Pahlav. In order to avenge his father, he left for Ctesiphon, "defeating every army of Azarmidokht that met". He then defeated Siyavakhsh's forces at Ctesiphon and captured the city.

Azarmidokht was shortly afterwards blinded and killed by Rostam, who restored Boran to the throne. However, in the following year a revolt broke out in Ctesiphon; while the Iranian army was occupied with other matters, the Parsig, dissatisfied with the regency of Rostam, called for the overthrow of Boran and the return of the prominent Parsig figure Bahman Jaduya, who had been dismissed by her. Boran was shortly killed, presumably from suffocation by Piruz Khosrow. Hostilities were thus resumed between the two factions. However, not long after both Rostam and Piruz Khosrow were threatened by their own men, who had become alarmed by the declining state of the country. Rostam and Piruz Khosrow thus agreed to work together once more, installing Khosrow II's grandson Yazdegerd III on the throne, putting an end to the civil war.

Aftermath and impact

The Sasanian Empire was greatly weakened when Yazdegerd III ascended the throne. The young king did not have the authority required to bring stability to his extensive empire, which was swiftly falling apart due to ceaseless internal conflicts between the army commanders, courtiers, and powerful members of the aristocracy, who were fighting amongst themselves and wiping out each other. Many of the governors of the empire had proclaimed independence and carved out their own kingdom. The governors of the provinces of Mazun and Yemen had already asserted their independence during the civil war of 628–632, thus resulting in the disintegration of Sasanian rule in the Arabian Peninsula, which was uniting under the banner of Islam. The empire came to resemble the Parthian feudal system that existed before the fall of the Arsacid Empire.

Yazdegerd, although being acknowledged as the rightful monarch by both the Parsig and Pahlav factions, did not seem to have held sway over all of his empire. Indeed, during the first years of his rule coins were only minted in Pars, Sakastan, and Khuzestan, approximately corresponding to the regions of the southwest (Xwarwarān) and southeast (Nēmrōz), where the Parsig was based. The Pahlav, who were mainly based in the northern portion of the empire, refused to mint coins of him. The empire was also at the same time invaded on all fronts; by the Göktürks in the east, and by Khazars in the west, who raided Armenia and Adurbadagan. The Sasanian army had been heavily weakened due to the war with the Byzantines and internal conflict. The circumstances were so chaotic, and the condition of the nation so alarming, that "the Persians openly spoke of the imminent downfall of their empire, and saw its portents in natural calamities." The empire would soon meet its end at the hands of an Arab invasion, during which Yazdegerd was killed in 651, possibly at the instigation of one his own subjects.