Yazdegerd III

After Ḵāled b. al-Walid’s raid of 633, the Persians won the Battle of the Bridge (634) but lost at Buwayb (635). Then ʿOmar sent Saʿd b. Abi Waqqāṣ. Rostam son of Farrukh Hormizd faced him at Qadisiyyah with a large army and thirty elephants. After four months a three-day battle was fought; Rostam was killed and his army collapsed.

Lewental says storytellers shaped most details; Ṭabari gives the battle 167 pages. In his view later memory telescoped the conquest of Iran into this one battle, although Qadisiyyah was not conclusive: Jalula and Nahavand followed, and Iran resisted stiffly for years. Saddam Hussein used the name Qadisiyyah as propaganda in the Iran–Iraq war.

Morony lists the explanations offered for the fall: class and religious strife, the absence of popular support for an elitist regime, conflict among the nobles, dynastic instability and the cost of the long war with Byzantium. Some 4,000 Iranian soldiers joined the victors. A state its people see no gain in keeping stands alone on the hard day. This is our reading.

After Qadisiyyah Saʿd reached al-Madāʾin. The garrison of Vēh-Ardašīr, on the west bank of the Tigris, abandoned it and cut the floating bridge, but the Muslims forded the river. Yazdegerd sent his family to Holwan and fled. Saʿd captured most of the royal treasure, and the people in the White Palace surrendered in return for tribute.

Morony says Iraq was the most important part of the empire: the capital, the apex of the administration and about one-third of annual tax revenue. With it went the royal treasure and many soldiers and nobles.

A state that draws its revenue from one fertile plain collapses when it loses that plain.

Yazdegerd raised a new army in the Jebāl and sent it to Nahavand. ʿOmar combined the Kufan and Basran forces under al-Noʿmān b. Moqarren. The battle lasted several days; al-Noʿmān and the Persian commander, Mardānšāh son of Hormoz, were both killed. The Muslim victory opened the Iranian plateau.

Morony says the course of the battle is difficult to reconstruct in tactical terms; the sources credit a ruse or arriving reinforcements. Its date is disputed too. The diagram below is schematic.

After Nahavand the cities surrendered one by one on tribute terms. In the terms for Ray and Azarbaijan, Morony says, fire temples were not to be destroyed nor the people killed or enslaved. Terms that secured life and property for tribute looked more useful to many people than fighting for a fleeing king.

Yazdegerd went from Isfahan to Istakhr and Gur, then to Kerman and Sistan, and finally to Marw. Morony says that, impecunious and arrogant with a large retinue, he alienated the marzban of Kerman and lost the governor of Sistan by demanding tax arrears. Māhūya, marzban of Marw, allied with the Hephthalite Nēzak Ṭarḵān. Yazdegerd was killed by a miller as he fled.

Ṭabari himself says there is “a difference of opinion regarding the cause of his murder” and gives several versions: the Turks were called in or not, the miller killed him for his belongings or on Mahawayh’s orders. In one, a priest warns Mahawayh that “religion and kingship are twins”. In Ṭabari’s account the Christian bishop of Marw took his body from the river and buried it at Istakhr.

The last king was undone not by the enemy but by his own governor, who refused him money. A king who can no longer give security but still demands taxes loses his subjects’ support. This is our reading.

Peroz, Yazdegerd’s son, went to Ṭoḵārestān. According to the Xin Tangshu he established himself in Sistan with help from its rulers; the Tang court recognised him in 661 as head of the “Persian Area Command” with its capital at Zaranj, and in 662 titled him “King of Persia”. Around 663 the Arabs defeated him, and he came to Chang’an in 673–674 and again in 675. In 677 he obtained permission to build a “Persian temple”, probably a Christian church, and he died around 679. His beheaded statue, identified by a Chinese inscription, still stands at Gaozong’s tomb at Qianling. His son Narseh set out with the general Pei Xingjian, but Pei abandoned him at Suyab. Narseh fought in Ṭoḵārestān for twenty years and returned to China around 707–709, where he died.

Compareti says the Jiu Tangshu confuses Peroz and Narseh and the Xin Tangshu is more reliable. He sees Pei Xingjian’s real mission as taking Suyab from the Turks; China had diplomatic contacts with the Arabs since 651. Embassies under the name “Persia” reached Chang’an until 755.

Great powers use exiles as long as they are useful. The Sasanian prince received titles, not armies.