Battle of al-Qadisiyyah (636): The Fall of Sasanian Iraq

The Battle of al-Qadisiyyah was fought around November 636 on the desert edge of southern Iraq between an Arab Muslim army under Sa’d ibn Abi Waqqas and the forces of the Sasanian Persian Empire under the general Rostam Farrokhzad. After several days of hard fighting the Persian army was broken and Rostam was killed. The victory opened Mesopotamia, the richest province of Persia, to the Arabs and began the fall of a dynasty that had ruled Iran for four centuries.

Background

The Sasanian Empire, founded in 224, ruled Iran and Iraq from its capital Ctesiphon on the Tigris. By the 630s it was in deep crisis. The long Byzantine-Sasanian War of 602–628 ended in defeat, King Khosrow II was overthrown and killed in 628, and a series of short-lived rulers followed. In 632 the young Yazdegerd III was placed on the throne, with real power held by great nobles such as Rostam Farrokhzad.

Meanwhile the Rashidun caliphate in Medina had united Arabia. From 633 Arab forces under al-Muthanna ibn Haritha and Khalid ibn al-Walid raided and conquered towns along the Euphrates, including al-Hira. In 634 the Persians crushed an Arab army at the Battle of the Bridge, but the Arabs won at al-Buwayb soon afterwards.

Caliph Umar ibn al-Khattab then raised a larger army from across Arabia and gave command to Sa’d ibn Abi Waqqas, an early companion of the Prophet Muhammad. The Sasanian court in turn sent Rostam with a major army to drive the Arabs back into the desert.

The armies

Arabic chronicles, notably al-Tabari, give enormous figures, sometimes over 100,000 Persians against around 30,000 Arabs. Modern historians regard these numbers as unreliable. Fred Donner, for example, suggests the Muslim army numbered perhaps 6,000 to 12,000 men, and most scholars agree that the Persians were more numerous, though by how much is unknown.

The Sasanian army included heavily armoured cavalry, infantry levies, archers and war elephants. The Arab army was lighter, relying on mobile horsemen and infantry, and included veterans of the fighting in Iraq and contingents from many Arabian tribes. Reinforcements from Syria arrived during the battle.

What happened

Before the fighting the two sides exchanged envoys. Arabic tradition preserves accounts of Arab delegates visiting Rostam’s camp and inviting the Persians to accept Islam, pay tribute or fight. These stories were shaped by later writers, but negotiation before battle was normal practice.

The battle itself lasted three or four days. Arabic sources give the days names. On the first day, the Day of Armath, the Persian elephants threw the Arab cavalry into disorder. On the second, the Day of Aghwath, Arab reinforcements from Syria arrived and the elephants were not in action. On the third, the Day of Imas, Arab warriors targeted the elephants, blinding or wounding leading animals until they stampeded back through the Persian ranks.

Fighting continued through the night, remembered as the Night of Harir (Laylat al-Harir) from the noise of battle. On the following morning the exhausted Persian line gave way. Tradition says a strong wind blew dust into the Persians’ faces and tore away Rostam’s tent. Rostam was killed, and much of his army was cut down as it retreated across canals and the Atiq channel. The great Sasanian battle standard, the Derafsh Kaviani, was captured.

Sa’d ibn Abi Waqqas reportedly directed the battle from a fortified building because he was ill. Losses are unknown, but both sides suffered heavily.

Why the Persians lost

The Sasanian Empire still had great resources in 636, and its army included some of the best heavy cavalry in the world. Its defeat had several causes. The dynasty had been weakened by years of civil war after 628, when a rapid succession of kings and queens held the throne in about four years. Many nobles were more concerned with their own provinces than with the court at Ctesiphon, and cooperation between them was poor.

The war with Byzantium had also emptied the treasury and damaged the agriculture of Mesopotamia. Severe flooding of the Tigris and Euphrates around this period had broken irrigation works, and an outbreak of plague in 627–628 had killed many people, possibly including King Kavad II.

Rostam himself is said in the Arabic sources to have been reluctant to fight a pitched battle, preferring to wear down the Arabs, but he was pressed by the court to attack. His army was large but slow, and once its elephants were turned and its commander killed it had no clear way to recover.

By contrast, the Arab army was united by religion, experienced after years of fighting along the Euphrates and backed by a determined caliph. Its reinforcements arrived at the right moment, and its leaders made use of the desert behind them as a safe base.

Key people

• Sa’d ibn Abi Waqqas (died c. 674): one of the earliest converts to Islam and commander of the Muslim army. He later founded the garrison city of Kufa.
• Rostam Farrokhzad (died 636): a powerful Persian noble from Khurasan and the leading figure at the Sasanian court, killed in the battle.
• Yazdegerd III (reigned 632–651): the last Sasanian king, who did not take part in the battle.
• Umar ibn al-Khattab (caliph 634–644): organised the army from Medina and corresponded with Sa’d during the campaign.

Consequences

With the main Sasanian army destroyed, the Arabs advanced across the Euphrates. In 637 they took Ctesiphon, the Persian capital, after Yazdegerd fled. The treasures of the royal palace fell into Arab hands and were divided among the soldiers and the caliphate. Later in 637 another Persian army was defeated at Jalula.

The Arabs founded new garrison cities to control Iraq: Basra in the south and Kufa near the battlefield, both established around 636–638. These camps grew into major centres of Islamic culture and politics.

Yazdegerd retreated to the Iranian plateau and raised another army, but it was defeated at the Battle of Nahavand around 642. After years as a fugitive he was killed near Merv in 651, and the Sasanian dynasty came to an end.

Legacy

Al-Qadisiyyah and Yarmouk, fought in the same year, are often paired as the two battles that broke the old superpowers of late antiquity. Within a generation Iraq and Iran became part of the Islamic world, although Persian language, administration and culture went on to shape the caliphate deeply.

The battle has a strong place in later memory. In Firdowsi’s Persian epic, the Shahnameh, it marks the tragic end of the old Iranian kings. In modern times the name has also been used for political purposes: during the Iran-Iraq War of 1980–1988 the Iraqi government called its war effort “Saddam’s Qadisiyyah”, invoking the ancient victory.

Timeline

• 628: Khosrow II is overthrown; years of instability follow in Persia.
• 632: Yazdegerd III becomes king of the Sasanian Empire.
• 633: Arab forces campaign along the Euphrates and take al-Hira.
• 634: Persian victory at the Battle of the Bridge, followed by an Arab victory at al-Buwayb.
• c. November 636: Battle of al-Qadisiyyah; Rostam is killed and his army destroyed.
• 637: Arab capture of Ctesiphon; Persian defeat at Jalula.
• c. 642: Battle of Nahavand ends organised Sasanian resistance.
• 651: Yazdegerd III is killed near Merv.

Why it matters

Al-Qadisiyyah ended Sasanian control of Iraq, the economic heart of the Persian Empire, and set in motion its collapse. It brought Mesopotamia and then Iran into the Islamic world, changing the political, religious and cultural map of western Asia for centuries.