The advent of Islam in the 7th century AD made a decisive change in the course of Iran's history. Apart from introducing a new religion into the country, it changed the nation's culture, language, script and civilization beyond recognition. The two centuries of Arab rule in Iran had a larger impact on its culture and mindset than had the invasions of the Romans or Alexander prior to it. It created a new Persian Muslim civilization and identity introducing a vast array of new theological and cultural concepts into the existing Iranian society.
== Early Interaction between Muslims and Sassanid Iran ==
Most of the modern-day Arabia had been conquered by Khusro Anushirvan and added to the Empire during his military campaign against Yemen. The Prophet of Islam, Muhammad was born in 570 during the reign of Khusro Anushirvan and was hence, a subject of the Sassanid Empire. Later, in his life, he is said to have expressed a sense of pride and good fortune in being born during the reign of an enlightened monarch as Khusro Anushirvan.
=== Muhammad's Letter to Khusro Perviz ===
Muslim missionaries claim that Prophet Muhammad sent Khusro Perviz the Sassanian monarch a messenger with a letter exhorting him to convert to Islam. Khusro Perviz reportedly tore them apart and contemptuously dismissed the messenger at which Prophet Muhammad is said to have remarked: "May his kingdom tear apart". Devout Muslims believe that this was the reason that Khusro was imprisoned and killed later and that the realm of the Imperial Sassanids itself crumbled to pieces.
=== Salman Al Farsi ===
Moid Salman or Salman Al Farsi (Salman the Persian) was born Ruzbeh in a small village called Jayyan in the province of Isfahan in Sassanid Iran during the reign of Khusro Anushirvan. His father was the dehkan (an army officer and petty landlord) of the village. His family descended from a line of Sassanian nobles and from an early age, Ruzbeh was inducted into the Magian faith and tended to the keep of the holy fire.
Very early in his life, he came under the influence of some Iranian Christians and converted to Christianity. Under the advice of these people, he made a pilgrimage to Syria upon hearing that Syria was the home of the Christian faith. On his journey to Syria, he was captured and sold into slavery. Transported to Mecca, he made a chance acquaintance with Prophet Muhammad and was convinced that Muhammad was the Messiah. He immediately converted to Islam and became one of the Companions of the Prophet who released him from slavery. He travelled along with him and fought in the Battle of the Ditch against the Meccans and the capture of Damascus and in the battles of Al Qadesiyah and Nehavend against the Persian Sassanian Empire. He died at the age of 88 and was buried near Ctesiphon according to some accounts, in the year 35 of Hijra, or 655 AD.
=== The Story of Princess Shahrbanu ===
According to sources, Shahrbanu was one of the three daughters of Yazdegerd III, the last Sassanian Emperor who was captured along with her sisters following the Islamic conquest of Persia. The sources relate that she was brought in person before the Caliph Umar who decreed that she be conedmned to a life of servitude but was rescued by Ali, whose son Hussain, she married. Sources also relate that she was present at the Battle of Karbala in 680 in which Hussain ibn Ali was killed. Shahrbanu reportedly fled to the mountains of Rayy pursued by the troops of the Caliphate. But sources say that as the enemy caught up with her, the mountain split open and swallowed her up. There is a shrine built at the place where she was reportedly swallowed by the mountains which is an important place of worship for Shiites.
Western academic historians have cast serious doubts on the legend. According to the Encyclopedia Iranica:
Earlier sources such as Ibn Sad and Ebn Qotayba describe Husayn's wife as a slave, originally from Sindh, and make no reference to her being a princess. The first scholar to explicitly describe her as being of the Persian royal family was the 9th Century Arab philologist Mobarrad.
== The Sassanid-Arab Wars ==
=== Battle of Chains ===
This was not the first conflict between the newborn Rashidun Caliphate and the Imperial Sassanid Empire. The confrontation was the result of a series of incursions made into Persian territory by the Arabs. The battle was fought in modern-day Kuwait in the year 633. The Caliphate forces were commanded by Khalid ibn Walid while the Sassanian army was commanded by Hormuz. The Sassanian soldiers linked themselves with chains to prevent the Arab cavalry from breaking through. This gave the battle the name 'Battle of the Chains'.
In the lead up to the battle, Hormuz challenged Khalid to a duel and was slain. The Persian troops fell upon the Arab army but were routed and forced to retreat. They were heavy casualties on the Persian side.
=== Battle of the River ===
A second battle was fought between the forces of the Caliphate and the Sassanid Empire in Mesapotamia (modern-day Iraq) in 633. The Persians were led by Karinz while the forces of the Caliphate were led by Khalid. The Persians were defeated once again.
=== Battle of Walaja ===
Following the defeat at the Battle of the Chains and the Battle of the River, the Sassanian Emperor Yazdegerd III sent two large armies under Andarzagar and Bahman respectively to fight the Arabs near the town of Walaja to the west of the Euphrates in Iraq. Khalid adopted the tactic of double-envelopment first practised by Hannibal against the Romans in the Punic Wars. Khalid came under vigorous Persian assault and was forced to retreat but the Persians were surprised by two bodies of the Arab army which attacked from the rear. After a hotly contested battle, the Persians were defeated and slaughtered in large numbers. Andarzgar fled from the battlefield and escaped into the Arabian desert but died of thirst soon afterwards. It was a resounding win for the Arabs as the Persian troops numbered 30,000-50,000 men and the Arabs just 15,000. The Battle of Walaja was also one of the longest and fiercest battles fought by the Rashidun Caliphate, prior to Qadesiyah and Nehavend.
=== Battle of Ullais ===
The defeated Sassanian troops under Bahman and their Christian Arab auxilaries who had escaped the battlefield retreated across the Euphrates and gave battle to the pursuing Arabs at a place called Ullais. The Sassanian troops were heavily reinforced by troops from Ctesiphon under Jaban. The Christian Arab contingent was led by Abdul Aswad. The combined army numbered artound 70,000 compared to the Muslim army of 15,000. The battle was fierce and raged on for many days. At length, the Arabs won the upper hand and the remaining Persian soldiers were cut to pieces. The residents of Ullais were compelled to pay jizya and act as spies for the Muslims.
=== Battle of Al Hira ===
Soon after the conquest of Ullais, the forces of the Caliphate proceeded further eastward and gave battle at Al Hira, the capital of the now defunct Lakhimid kingdom. In May 633, Khalid attacked the fortress-city. The Lakhimid soldiers responded by hurling projectiles. But at length, the Lakhimids surredered and consented to pay jizya. With the victory at Al Hira, the conquest of Iraq was complete.
=== Battle of Al Anbar ===
Al Anbar or Perisabor or Firuz Shapur is a town in Iraq. It was built by the Sassanian king Shapur I. In 633, Khalid attacked the fortress of Anbar which was defended by a large Persian army commanded by Shirazad. The Battle of Al Anbar is often known as the "Action of the Eye" as the Muslim archers targetted the eyes of the defending Persian soldiers.The battle resulted in one more victory for the forces of the Caliphate.
=== Battle of Ein-ul-Tamr ===
Following the successful siege of the fortress of Al Anbar, Khalid attacked the frontier post of Ein-ul-Tamr to the west of Anbar. Ein-ul-Tamr was garrisoned by a body of Sassanians and their Arab Christian auxilaries commanded by one Aqqa ibn Qais ibn Bashir an Arab Christian. The Arabs successfully conquered the town and captured Aqqa.
=== Battle of Daumat-ul-Jandal ===
Daumat-ul-Jandal was one of the large commercial towns of Arabia, widely known for its rich and much-frequented market. It was also an important communication centre, a meeting point of routes from Central Arabia, Iraq and Syria. The city was defended by a garrison of Christian Arabs.
In August 633, Abu Bakr sent an army under Ayadh bin Ghanam to capture the city. But the siege lasted many days without any result. Ayadh appealed to Khalid for help. Khalid obliged and made way for Daumat-ul-Jandal. The battle lasted many days but the Christian Arabs were overwhelmed and slaughtered in large numbers.
=== Battle of Muzayyah ===
When Khalid ibn Walid left from Ain-ul-Tamr to Daumat ul jandal for the help of Ayadh, the Persian court believed that Khalid had returned to Arabia with a large part of his army. So Bahman was sent with an army of 15,000-20,000 men to fight the Arabs and drive them out of Iraq. There were two other Persian armies waiting at Saniyy and Zubail to support Bahman. In the last week of September 633, Khalid arrived at Hira from Daumat ul Jandal to fight the Persians. Khalid responded by dividing his army into three divisions and sent two of them against the Persians at Saniyy and Zubail while he himself fought Bahman's army. Khalid attacked the Persians initially but was unsuccessful. So he resorted to strategem and ordered a three pronged attacked by the Arabs on the encamped Persian troops at night by the three different divisions from three separate directions. Thousands were slaughtered but most of the Persians managed to escape in the darkness of the night. The Christian Arab armies at Saniyy and Zumail were vanqished in very much the same way.
=== Battle of Firaz ===
In January 634, the Persians allied with the Christian Arabs and Byzantine Empire and launched an attack on the Arabs. But in the battle which was consequently fought at Firaz the combined army was defeated and annihilated by the Arab troops led by Khalid. This decisive victory resulted in the Arab conquest of Iraq and was the prelude to the victory at Qadesiyah.
=== Battle of the Bridge ===
In October 634, emboldened by their early successes, the Arabs under Abu Ubaid launched an attack across the Sassanian frontier. The Sassanian general Bahman immediately took position near Kufa on the Euphrates. Intending to give battle, Abu Ubaid marched at the head of 10,000 troops and crossed the Euphrates on November 28, 634 by preparing a bridge of boats.
When the battle began, the Arab cavalry advanced but were opposed by the Persian war elephants. The Arabs soon lost ground and were forced to flee. Abu Ubaid was killed in the melee and the Arabs were forced to retreat. When Muthanna gathered his soldiers on the other side of the Euphrates only 3,000 Arab soldiers regrouped. The rest had either been killed or had fled the battlefield. This was the last Persian victory against the Arabs prior to the defeat of Yazdegerd in 636 and 642.
=== Battle of Qadesiyyah ===
==== Preparations ====
During the last few battles when Khalid was absent from Iraq, the Persians under their general Rostam sought to re-establish Persian authority by seething discontent amongs the inhabitants of the provinces along the western frontiers of the Islamic Caliphate.
The Persians administered a crushing defeat on the Arabs in the Battle of the Bridge, but internal dissention and discontent foiled their dreams of recovering lost territory. The Arabs made a splendid recovery during this period as reinforcements arrived from Arabia. Muthanna gave battle on the canal Al Boweib and succeeded in defeating them. The beaten army recrossed the Euphrates, and returned to Ctesiphon without suffering further losses. But the conquest of Iraq by the Arabs was complete and the whole of the Sassanian Empire was open to the invaders.
==== The Battle ====
In the year 636, the Persians made an extraordinary effort to recover lost territory. They dispatched an army of 60,000 under the command of the able and experienced Rostam Farrokhzad. The army crossed the Euphrates without much difficulty and entered the territory known as Sawad which was retaken with ease. The Arabs were driven back and gave battle at a place called Qadesiyah or Kadesia. They were lead by the great genera Sa'ad ibn Abi Waqas since Muthanna had passed away.
Rostam divided the Persian army into three division: the first under himself which comprised around 20,000 troops, the second and third under Jalenus and Bendsuwan respectively. Rostam himself took position at the centre while positioning his lieutenants on his right and left respectively. The Arab army was, meanwhile, made of 36,000 troops commanded by Khalid in the absence of Sa'ad who was injured.
The Arab cavalry charged first but was repulsed by the line of elephants which guarded the Sassanian rear. The Persians advanced pushing the Arabs back seeking to repeat the tactics of the Battle of the Bridge against the Arabs who were driven close to annihilation. However, the archers under Asim came to the rescue of their cavalry by shooting arrows at the Persian elephants. The day was, however, won by the Persians. The Arabs 500 men on the day.
On the second day, with fresh reinforcements from Syria, the Arabs attacked the Persians once again. The Persians charged with their elephants but were repulsed. There were light skirmishes and individual duels in which two of the leading Persian commanders Bendsuwan and Bahman Djulhadjib lost their lives. The Arabs conspired to capture Rostam himself but the latter was saved. The Persians had lost 10,000 in killed and wounded on the second day, the Arabs no more than 2000.
On the third day, the Persians reequipped their elephants to launch an all-out attack. But the horses of the Arabs had grown accustomed to the giant beasts. Morever, the Arabs adopted a new tactic to fight the elephant corps, which was to a fair degree, successful. They concentrated on injuring the elephants in their eyes or proboscis and this was fairly successful as when two of the elephants on the forefront were shot at by the Arabs the others too panicked and fled. The Arab cavalry pursued the fleeing Persians across the El Atik stream but the elephant corps was saved by the timely interposition of the Persian foot and horse regiments. The day came to an end without any of the sides taking a decisive advantage.
On the night of the third day, as the Persians slept soundly in their camps, they were attacked by two Arab contingents under Toleicha and Amr' killing a number of Persian soldiers.
On the fourth day, the Persians fought the Arabs with their backs to the east. This seemed to be a right move as they held the advantage for the early part of the day. However, about noon, all of a sudden a sadnstorm broke out from the west blowing sand into the eyes of the Persians. The Arabs, who had their backs to the eye of the storm, were relatively unaffected by the violent gusts ofn wind. Hormuzan, Satrap of Susiana, and Firuzan, fell back. Rostam dismounted his throne to protect himself from the sandstorm and took refuge amongst his mules. However, he was spotted by the Arab general Hillal who pursued the fleeing commander across the El Atiq stream and slaying him, mounted his throne shouting aloud:
There was a general panic and the bulk of the Persian troops tried to flee by crossing the El Atik stream but were cut to pieces by the Arab assailants. As many as 10,000 Persian troops perished in the El Atik stream, either by drowning or to the sword of the Arabs. A few of them stood their ground firmly and fought to the last while others managed to reach the other bank safely. The fourth day of battle resulted in a decisive victory for the Arabs; 36,000 Arab troops had annihilated a Sassanian army of 60,000
==== Aftermath ====
The retreat of the Persian army was conducted by Jalenus. Sa'ad sent three bodies of troops across the Atik who came up with this division and slaughtered it to a man. The remainder of the troops sought refuge within the walls of Ctesiphon.
=== Fall of Ctesiphon ===
In 637, a large Arab army comprising of 20,000 men crossed the Euphrates and penetrated into Sassanian territory once more. Yazdegerd III hurriedly vacated Ctesiphon for the safety of the mountains of Northern Iran. He barely had the time to package his personal belongings and a very small quantity of the treasures accumulated by his ancestors. Sa'ad meanwhile overran Mesapotamia and the Euphrates and entered the abandoned Persian capital of Ctesiphon finding the city undefended.
Ctesiphon was a coveted prize and the city was plundered in its entirety. Later, when the plunder was distributed equally amongst the 60,000 soldiers whom Sa'ad commanded, each soldier's share was found to amount to 12,000 dirhems. This had a huge impact on the empire's exchequer and it beacme imminent that the end of the state was near.
At the same time, the Arabs encountered such greatness and grandeur which was beyond all their imagination and eagerly grabbed all that they could lay their hands upon. Gibson describes the plunder in his usual anti-Islamic, offensive manner .
After the conquest of Ctesiphon, Hisham and El Qaqa were sent with 12,000 men against the fugitive Yazdegerd. The Sassanian general Mihran confronted him at the town of Jalula near Holwan with an army of 100,000 men. Jalula was taken by the Arabs with great slaughter -- over hundred thousand Persians were reported to have perished in the onslaught. The town was plundered andeach soldier was given a share of 10,000 dirhems.
After the defeat at Jalula, Yazdegerd withdrew from Holwan to the town of Rayy. Holwan was taken in a few days along with Shirwan, Mahsabadan and Tikrit.
In 639, the Arabs launched campaigns against Susa and Persia proper. The former was successful and they successfully captured the cioty of Ahvaz. However, the latter failed to achieve its objectives. In 640, Hormuzan the Persian satrap of Susa allied with Shahrek, the satrap of Persia proper and attacked the Arabs unawares. However,the rebellion was subdued and Hormuzan captured and enslaved. He was transported to Medina where he converted to Islam.
=== Battle of Nehavend ===
In 641, Sa'ad was recalled by the Caliph Umar who replaced him with Ammar Ibn Yaser. Taking advantage of this change, Yazdegerd conspired to recover his lost throne and sent envoys all over the provinces of Media, Azerbaijan, Khorasan, Gorgan, Tabaristan, Merv, Bactria, Sistan, Kirman and Persia proper (Pars). Within a few months, he was able to accumulate an army of 50,000 men. The Arabs deputed Noman, the Governor of Ahvaz, to repel a possible Sassanid invasion and he encamped near Nehavend with 30,000 men. Here, the troops faced each other for around two months, one of the two sides willinjg to initiate hostilities. At length, by a clever st5rategem, Noman, set afloat the rumor that the Caliph Umar was dead. Firouzan, who commanded the Sassanid troops, regarding it as an opportune moment to strike the encamped Arab troops, attacked them. The battle raged on for many days but at length, the Persians had to flee. Noman was killed by the retreating Persian troops but this had no effect on the result of the battle. The Sassanid army was trapped in the mountain passes and slaughtered to the last man. This extinguished the Persian army. Yazdegerd fled to Merv sending emissaries to India and China for help but to no avail. He made a last stand at MKerv till he was killed in 651. Merv fell to the Arabs in a few years thereby ending the Sassanian Empire.
=== Completion of the Conquest ===
Between 641 and 651, the Arabs conquered the rest of Iran. Persia proper (Pars) fell during the reign of Caliph Uthmann, Sistan a few years later and Merv, after the death of Yazdegerd III. In 656, the Arabs completed the conquest of Greater Khorasan with successful siege of Herat. Herat formed the Eastern frontier of the Rashidun Caliphate till it was replaced by the Umayyad Caliphate. Under the Umayyads, the Arabs expanded further and conquered Zabul, Bamiyan, Baluchistan, Makran and Sindh upto the banks of the river Indus.
== Consequences ==
The process of conquest of the Sassanian Empire began in 633 and came to an end in 656. Still, however, there existed principalities in Tabaristan (the modern day Tabriz) which never became a part of the Rashidun or the Umayyad Caliphates.
The Islamization of the conquered provinces began soon after the conquest and went on for hundreds of years. Poll tax or jizya' was imposed on non-Muslims thereby encouraging the populace to convert. The Persian language was identified with a quasi-national feeling and was prohibited by the Umayyads, its usage being substituted by Arabic. Persians were reduced to a position of slavery and subordination. The nation was plundered to the extremes to fill the coffers of Damascus.
However, Umayyad rule was brought was brought to an end by the revolt of the Abbasids. Despite the fact that it was fought for the replacement of one Arab dynasty by another, the movement itself was organized by Iranians and led by an Iranian general Abu Muslim.
== Viewpoints about the Islamic Conquest of Iran ==
The two principal viewpoints about the Islamic invasions have been explained in detail by Professor Bernard Lewis:
== References ==
See Bibliography Section