What if the Battle of Qadisiyyah Had a Different Result?

Figure 1. Image of a Zoroastrian temple. The Zoroastrian religion began to decline after the battle's results.

The battle of Qadisiyyah was fought in 636 CE from November 1-4. The battle is not known well in Western history but it had major implications for the West and much of the globe. This was a battle where the Arab armies, newly converted to Islam, were able to defeat the Sasanid Persian Empire. The result was the conquest of what is now Iraq and eventually Persia, allowing the new Islamic Empire to emerge in the Middle East and, eventually, expand to other areas.

The Historical Circumstances

In 636 CE, the followers of two major universal religions, which were Christianity and Zoroastrianism, were at war with each otehr. These faiths were supported by the two major superpowers of the Middle East, which were the Byzanitine and Sasanian Empires. Both these powers seemed invincible and held great wealth. However, by the early 7th century CE, major wars across the Middle East devastated much of the region and led to both these empires to deplete their resources.[1]

In 636, Caliph Umar had re-invaded Iraq, after a previous Muslim army was defeated and removed from the region. The Sasanian and Arab armies met at the village of Qadisiyyah, southwest of the modern city of Hilla in Iraq, which is near ancient Babylon. The battle was mostly fought by a relatively inexperienced Arab army; however, much of the Persian army was also inexperienced, as many of their best troops had died or were depleted from previous engagements. This made the two sides relatively even and after the first day of the battle it did not seem that either of them could break each other's defenses. A key turning point was Arab reinforcements that strengthened the Islamic army, who were much more professional soldiers and well trained, and that arrived at the battle of Qadisiyyah on the second day. These numbered about 5000 and proved to be the difference in allowing the Arabs to breakthrough the Persian main line, not only bolstering the Arab army but also giving them more confidence, causing them to defeat and force the main Persian force to retreat. By the fourth day of the battle, the outcome was clear and the Sasnian army fled to the north, although many were killed as they attempted to flee.[2]

With the main Persian army shattered, key outcome now became evident after the battle. First, the Arab army plundered an extraordinary amount of loot from the Sasanian army. This helped finance later battles and the Muslim army's march north. Second, with no major army left to face, the Arab army was now able to march to Ctesiphon, the great Sasanian capital. After a two month siege, the capital fell and the Arabs, for the first time, had conquered a major metropolis that was a truly global city. Ctesiphon had major trade connection that spanned almost the extent of the Old World. The loss of the city also led to the full conquest of Mesopotamia and Khuzestan, which were the most important provinces in the Sasanian Empire. In 650, a new phase of invasions was then ready, leading to the conquest of Persia and defeat of the Sasanian Empire.[3]

Implications of the Battle

Figure 2. The Arabs were able to expand after the battle and fight the Byzantines, ultimately being checked at the gates of Constantinople.

Typically, the fall of one empire, in this case the Sasanian, and rise of another, the Islamic Empire, which became the Umayyad and later Abbasid Empire, as well as spawning other states, would not be that different from other succession of empires that was typical in the 1st millennium CE. However, the battle at Qadisiyyah and subsequent conquests it enabled allowed many social changes to occur that proved to spread to many regions.

First, the fall of the Sasanians, which became inevitable after the battle, weakened support of the Zoroastrian religion and many adherents eventually converted to Islam after the fall of the Sasanian empire (Figure 1). In effect, it allowed one religion to be mostly replaced by another. Although this process occurred over a long period, the events at Qadisiyyah accelerated this process.[4]

Second, the defeat of the Persians paved the way for major Arab migrations to Iraq and more fertile regions of the Middle East. Although Arabs were present before in many towns and cities in the Middle East, this now meant the Arabic language started becoming more prominent as migrants came to different regions. With the use of Arabic in Islam, it cemented the spread of this new common language to be widespread across not only the Middle East but it soon spread to Iran and west to North Africa.[5]

Third, the battle gave the Islamic armies a lot of confidence and experience. This led to much more rapid gains in the Middle East and North Africa against the Byzantines. While the Arabs never defeated the Byzantines, they solidified their hold on the Middle East. Between 646 and 732, the Arab armies had almost been unstoppable in open battlefields, although sieges of great cities, such as Constantinople, gave them more difficulty (Figure 2).[6] The Arab was only stalled by Charles Martel's victory in 732.

Finally, the Arab armies benefited from the technical know how and infrastructure built by the Sasanians in and around Iraq. This allowed them to build using new technical capabilities they acquired and developed using Persian and Classical science. Furthermore, scholars who were based in Persia, who had come from many parts of the ancient World, including Greece and India, were employed by the Arabs. This allowed not only the great Golden Age of Arab science and philosophy to be possible, and thus develop indigenous new discoveries, but it also allowed much of the lost knowledge in Europe, after the collapse of Rome, to be copied by the Arabs. This knowledge was then transferred back to Europe in the Medieval period, eventually helping to influence the Enlightenment that allowed a new period of discovery to emerge in Europe.[7]

Alternative Possibilities

If the battle resulted differently, where the Muslim armies could have been routed, then one possibility would be that Islam and the Islamic Empire would have found it harder to expand outside of Arabia. If the Sasanians were able to hold to their power then it would have been difficult for another major rival power to emerge in the Middle East. In effect, the Sasanians had to be defeated for the Islamic Empire to expand and for Islam to spread. In religion, this would have likely meant that Zoroastrianism, rather than an obscure religion today, could have remained relatively prominent and may have even expanded to other regions, perhaps even rivaling Christianity in places. Many of the tenants, good versus evil, resurrection of the dead, and judgment day were present in this religion, which could have made it attractive for some populations. The Arab language would have been far more obscure as well, while Persian and Greek, spoken by the Byzantines, could have become more common languages across the Middle East. Cities such as Baghdad would have likely not been founded, while the city of Ctesiphon, which was likely the largest city in the 7th century CE during the battle for Qadisiyyah, would have remained as the cosmopolitan center of the Sasanian Empire. It is hard to know if Jacobite Christianity, and Eastern Christianity in general, including the various Orthodox faiths, would have thrived in the Middle East if the outcome of Qadisiyyah would have been different, as the conflict between the Byzantines and Sasanians would have likely remained.[8]


Battles are often decisive moments in history that prove one direction or path in history could be undertaken based on the outcome. This was the case at the Battle of Qadisiyyah, where the Islamic army was able to not only triumph but the results of the battle allowed them to surge into what is today Iraq and gain a new confidence and finance their campaigns that helped propel their other expansions. The results probably would have been very different if the battle was lost by the Arab army, as the Sasanian Empire would have been in better position to then dominate the Middle East. Religion and language changes are the most visible outcomes from the battle's significant results. However, the results also influenced how the Arabs eventually created contacts with Europe, where important Classical works and philosophy was transferred back to Europe, including new developments in Persian and Arab sciences and philosophy, that helped to launch the Enlightenment centuries later.


  1. For more on background to this period, see: Cutler, Anthony. 2009. Image Making in Byzantium, Sasanian Persia, and the Early Muslim World. Variorum Collected Studies Series. Farnham, Surrey, England ; Burlington, VT: Ashgate/Variorum.
  2. For more on the battle, see: <Madelung, Wilferd. 1998. The Succession to Muhammad: A Study of the Early Caliphate. Cambridge: Cambridge University Press.
  3. For more on the conquest of the Middle East by the Arab armies and invasion and conquest of Iran, see: Savant, Sarah Bowen. 2013. The New Muslims of Post-Conquest Iran: Tradition, Memory and Conversion. Cambridge Studies in Islamic Civilization. Cambridge ; New York: Cambridge University Press.
  4. For more on the replacement of the Zoroastrian faith in many places, see: Rose, Jenny. 2011. Zoroastrianism: An Introduction. Introductions to Religion. London: I. B. Tauris.
  5. For more on the migrations that followed the conquest of Iraq, see: Sharqāwī, Muḥammad. 2010. The Ecology of Arabic: A Study of Arabicization. Leiden; Boston: Brill, pg. 166.
  6. For more on Arab and Islamic conquests and defeats after Qadisiyyah, see: Hoyland, Robert G. 2015. In God’s Path: The Arab Conquests and the Creation of an Islamic Empire. Ancient Warfare and Civilization. Oxford ; New York: Oxford University Press.
  7. For more on how Arabs incorporated Persian and Classical science and knowledge, see: Al-Khalili, Jim. 2010. Pathfinders: The Golden Age of Arabic Science. London: Allen Lane.
  8. For more on the significance of the conquest of Islam and fall of the Sasanians, see: Crawford, Peter. 2014. The War of the Three Gods: Romans, Persians, and the Rise of Islam. First North American edition. New York, NY: Skyhorse Publishing.