The invasion of Iran by the Arabs, came as a crippling blow to the great Iranian nation which had been so proud of its ancient and brilliant civilization, and its success against Byzantium and Rome. But in reality Iran had been exhausted by excessive wars, and the country was in anarchy as a result of incessant dynastic quarrels and court intrigues. Ctesiphon, the capital of the Sassanid Empire, was taken in AD 637. Less than twenty years later, before the death of the third Caliph, the Arab invasion had reached every region of the Iranian plateau as far as Balkh, except Makran and the lands which lay beyond it. This invasion was too rapid to be considered an occupation or a definitive conquest. However, the installation of strong garrisons in towns such as Shiraz, Nahavand and Ahvaz enabled the Arabs to keep a foothold while waiting until the settlement of the revolts caused by their intrusion allowed them to consolidate their position.
The Zoroastrians, although outwardly accepting Islam, continued to practice their religion, especially in Fars and Azerbaijan. Others found refuge in the various mountain massifs of the plateau, where they lived under the authority of small local dynasties. The first emigration of Zoroastrians to India took place in AD 700. Armed resistance was particularly tenacious on the shores of the Caspian Sea, where coins were still minted in the image of the Sasanian kings. The hereditary chiefs of this region remained independent, although numerous expeditions were sent to subdue them. In the eleventh century, Pahlavi writing was still used in the inscriptions on the monuments of the north slope of the Alborz, several of which still exist.
On the other hand whole groups of Yazdgerd’s army apparently went over to the Arabs of their own accord and many Persians were converted so as to avoid paying heavy tax imposed on non-Muslims, or simply to be on “the side” of the conquerors. Moreover the conquest brought Muslim Arabs to Iran – tradesmen, craftsmen and other workers – in ever-increasing numbers during the Umayyad Caliphate, but Iranian opposition still formed an obstacle for some time to the conversion of the country to Islam. The delegates of the governors of Basra and Kufa, who administrated the eastern regions of Iran, had a hard time performing their functions. Khorasan rebelled and their manifold troubles continued until a large garrison had been installed at Marv and, shortly afterwards, 50,000 Arab settlers, so it is said, had been settled with their families in Khorasan.
The Islamic conquest had left large groups of Iranians antagonistic to Muslim doctorine. For the thing the Arabs did not treat the new converts as equals and they in turn were dissatisfied on finding that they were under the yoke of people they looked on as intruders and upstarts. Highly sensitive to the contempt of the Arabs whom they despised, they supported, as did the non-converts, the political and religious claims of the Abbasid family, descendants of an uncle of the prophet, Abbas from the union of the supporters of Ali. A force which was opposed to the Umayyads was born. Khorasan joined the faction and after a series of battles which took place during the seventh century the Abbasid dynasty replaced the Umayyad dynasty.
The situation of the Persians, not only in the Islamic world but also in Persia itself, was suddenly entirely transformed. Whereas they had been excluded from high office by the Umayyads, they were nominated to the most important posts in the new court of the Caliph, which was transferred from Damascus in a Semitic country to Baghdad, a stone’s-throw from the site of Ctesiphon, the capital of the Sassanian Empire. The Persian tradition and way of life assumed considerable importance in the new center of Political power. The Caliphs chose their ministers and councilors from the great families of Persian origin. One of these families, the Bermakids, actually had a predominant role in running affairs of state for several decades.
Harun al-Rashid, the Caliph, put an end to this legendry favoritism of one family, but Persian influence continued to predominate at the Abbasid court, especially during the Caliphate of his son, al-Mamun, whose mother and wife were Persian. But for this very season, because of an almost offensive use of Persian customs, fashions and splendor, a change or rather an attempt at a change took place. The tenth Caliph, planned to make Damascus the capital of the Arabian Empire once more so as to avoid living in the Iranian atmosphere of Baghdad which he considered corrupt. Later he undertook the construction of an entirely new capital, north of Baghdad, at Samarra on the Tigris.
During this period of anarchy the governors of the Iranian provinces which had been converted to Islam gradually broke away from the Abbasid Caliphate, founded minor national dynasties in the ninth and tenth centuries.
In western Iran the new national Persian spirit showed itself in the form of small local powers, such as the Ziyarids who dominated a part of the Iranian plateau for a certain time and were later confined within the boundaries of Tabarestan and Gorgan.
First of all one must explain how a pre-Islamic Iranian monument differs from other Iranian monuments of the Islamic period. It must be clearly understood that it is not a question of comparing a Sassanian palace with a mosque on the Arabian plan, in other words with an imported type of edifice imposed on Iran which disappeared after a few centuries of use, but with monuments of purely Iranian origin – for example comparing the palace of Firoozabad or Sarvestan with Jame mosque at Isfahan or the Timurid Madreseh of Khargerd. Each of these four buildings is an arrangement of ivans and domes on a square plan, the same sort of ivans and the same domes.
What is different is not the construction nor the forms, nor even the plan, for there is not really much difference between that of the palace of Firouzabad and that of the Timurid madrasa of Khargerd, but the appearance, the dress in which Islam clothed the Sassanian monuments, the spirit with which it attempted to imbue Iranian architecture, as with all the peoples it dominated.
Muslim architecture has long passed for a simple aggregate of constructional procedures and decorative formulae adapted by Islam from the techniques of the peoples under its domination. The undeniable originality of its productions seemed to be the result of the unification of these various techniques and the unification itself the result of their adaption to the special needs of the Muslim world.
If this were so the history of the origins of Islamic architecture would be no more than the enumeration of the various origins of pre-existing elements, the observation of the successive stages of the automatic process of assimilation. The whole point for the historian would then be weigh up definitively the contribution of each civilization in order to deduce, as has been done, that Muslim architecture was mainly Iranian, or Egyptian, or Byzantine, or even Roman, or more simply still that was Coptic in Egypt, Byzantine in Syria, Iranian in Iran, etc, which when all is said and done, would reduce it to nothing.
But today the notion of the study of an art merely from the material point of view is no longer accepted. Art is not stone, brick, words or tricks of the trade; it is above all the reflection of the artist’s soul, the visible expression of the forces which drive him, and architectural technique, like language, is only a means of expression, an instrument in the service of the mind. In the same way that what first matters in literature is the writer, what counts in architecture is the architect. What counts in the architecture of a people is the collective soul of that people. To some people architecture is not so much a certain way of building as the visible expression of the harmonious soul of Greece; the origin and development of Roman architecture lie completely, in the qualities of order and power, in the massive force and utilitarianism which characterize the Roman mind; Byzantine architecture is the complex reflection of the Helleno-Asiatic soul of Byzantium; that of our great European cathedrals is an elevation, a prayer.