This is a transcript of a talk I gave at the Palais des Beaux-Arts in Brussels on 10 May 2015 on ‘The many roots of Christian Europe, the many sources of the Islamic world’. It was part of a series of talks to accompany an exhibition of ‘The Ottoman Orient in Renaissance Art’ entitled ‘L’Empire du Sultan’.

---

I want to begin this talk in two cities at opposite ends of Europe – Córdoba and Istanbul. Córdoba’s Mosque-Cathedral is one of the most glorious buildings, not just in Spain, but in Europe. I was last there some 20 years ago. But the memory is still vividly etched in my mind. I remember walking through the courtyard of orange trees, the trees are arranged in rows, the deep green of their foliage splashing colour upon the dusty monochrome of the walls and the ground. And then, almost if they had changed form, the rows of orange trees give way to a forest of columns of red-and-white arches that signal the mosque. The transition is stunning, as is the mosque, whose beauty, spacious and peaceful, is almost impossible to covey in words rather than in the experience. And then, as you walk through, there comes another transition – to a Renaissance cathedral that squats like a familiar stranger within. It would be difficult to call the cathedral beautiful. But there is something quite remarkable about it.

Córdoba’s mosque-cathedral is an architectural expression of the complex, intricate story of Europe. And, for some, that is the problem. In recent years the Cathedral Chapter of Córdoba, the branch of the Catholic Church that administers the site, has slowly wiped away the word ‘mosque’ from the monument’s title and from the publications about the site, officially calling simply the ‘Cathedral of Córdoba’. Even on Google Maps, the building was for a while simply labelled the Cathedral of Córdoba, before an online protest restored the original name of Mosque-Cathedral.

On visiting the mosque cathedral today, you are led first to excavations of mosaics from the Basilica of Saint Vincent. ‘It is a historical fact’, the official brochure tells us, ‘that the Basilica of Saint Vincent was expropriated and destroyed in order to build on top of it the subsequent Mosque in the Islamic period.’ The suggestion is that the site is really Christian, and that Muslim Córdoba’ was but a footnote to the city’s Christian history.

The story is more complex. The first Muslim armies came to Iberia in the first decade of the seventh century. By the middle of the century, al-Andalus, or Muslim Iberia, occupied most of what is now Spain and Portugal, and stretched into France, beyond Arles to Septimania. It was the Western part of the great Islamic empire.

Córdoba, the capital of al-Andalus, had become, by the tenth century, perhaps the most important city in Europe. It was a centre of learning, rivaled only by Bagdad, the other great city of the Islamic empire at this time. The caliph’s library in Córdoba comprised, it is said, almost half a million books.

The heart of the city was the mosque, or Mezquita. The Church of St Vincent once stood on the spot where the mosque was eventually built. Abd al-Rahman I, the founder of the Umayyad dynasty in Iberia (his family had been deposed as caliphs from their capital of  Damascus) purchased half the church to use for Muslim worship. In 784 he struck a deal with the Christian community. He bought the other half of the church to be able to erect upon the site a new mosque that he hoped would rival in magnificence those of Baghdad, Jerusalem, and Damascus, and be talked about with as much reverence as that of Mecca. In return, Christians were given in addition to payment for their part of the original church  permission also to rebuild another one.

The original mosque was a remarkable architectural hybrid, fusing the artistic values of East and West, adopting Roman and Visigoth techniques, and including elements previously unknown in Islamic religious architecture such as the use of double arches to support the roof, and the blending of stone and brick. It was vast enough to hold 40,000 people. Nor was the Mezquita just a religious house; it was also Córdoba’s university, and one of the great centres of learning in the world, in reputation rivaling even that of Bagdad.

The Mezquita was held in such esteem even by Christians that when the king of Castille Ferdinand III reconquered Córdoba in 1236, his army did not, as it normally would have done, destroy it. It became a place of Christian worship, and small architectural alterations were forced upon it. But for three centuries the main structure of the Mezquita was left untouched. In the 16th century Spanish King Carlos V gave permission to the Church authorities (against the wishes of Córdoba’s city council and local Christian worshippers) to rip out the centre of the Mezquita to construct a cathedral. Much of the old mosque was left intact, including the glorious mihrab, or prayer niche, and the celebrated red-and-white horseshoe arches. Nevertheless, when Carlos V visited the completed cathedral in 1526, he was said to have been shocked by the damage wrought on the mosque, exclaiming ‘You have built here what you or anyone might have built anywhere else, but you have destroyed what was unique in the world.’

Three thousand kilometers away at the other edge of Europe stands Istanbul. And at the heart of Istanbul is the glorious Hagia Sophia, one of the great cathedrals of the world. Istanbul once occupied the same role in eastern Christendom as Córdoba played in the Western Islamic Empire. And Hagia Sophia was to Istanbul as the Mezquita was to Córdoba. And in Istanbul today a similar debate is taking place over the fate of Hagia Sophia, a debate that is the mirror image of that in Córdoba

The current church that we know as Hagia Sophia (or ‘divine wisdom’) is built on the ruins of two previous churches on the same site. It was commissioned by the Emperor Justinian, the last Latin-speaking ruler of what was then the Eastern Roman Empire, and completed in 537. It was built with extraordinary speed – it took five years to complete as compared to the century for the construction of Notre Dame. Yet it was a most remarkable building, at once the culminating architectural achievement of late antiquity and the first masterpiece of Byzantine architecture. ‘I say, renowned Roman Capitol, give way! My Emperor has so far overtopped that wonder as great God is superior to an idol’, wrote the astonished Greek poet Paulus Silentiarius when he first set eyes upon the church. Justinian himself is said to have remarked, ‘Solomon, I have outdone thee’.

Most remarkable, perhaps, is the huge dome, that rests on pendentives, spherical triangles that arise from four huge piers that carry the weight of the cupola. ‘It seems not to be founded on solid masonry, but to be suspended from heaven’, wrote Procopios, the last great historian of the ancient world. A millennium later the Ottoman historian Tursun Berg was to write with equal wonder: ‘What a dome, that vies in rank with the nine spheres of heaven! In this work a perfect master has displayed the whole of the architectural science’.

Beneath the dome are forty windows through which sunlight suffuses the interior, illuminating the gold mosaics with such softness that it can conjure up, for believers and non-believers alike, a sense of ineffable mystery. Hagia Sophia cast an enduring shadow upon the Eastern Orthodox, Catholic, and Muslim worlds, influencing the development of both architecture and forms of worship.

Hagia Sophia became the seat of the Orthodox patriarch of Constantinople and the spiritual heart of the Byzantine empire. In 1453, the city was captured by the Ottomans. Mehmed II, leader of the Ottoman forces, rode to Hagia Sophia,  or so the story goes, dismounted at the door of the church and bent down to take a handful of earth, which he then sprinkled over his turban as an act of humility before God.

Constantinople was renamed Istanbul. Hagia Sofia was turned into a mosque. It too was renamed Aya Sofya, and became the first imperial mosque of Istanbul, coming eventually to boast four minarets. In the centuries after the Ottoman capture of Istanbul, Aya Sofya was rebuilt, restored and extended many times.

After the fall of the Ottoman Empire in 1922, the abolition of the Caliphate two years later, and the establishment of the secular republic of Turkey under Mustafa Kemal Atatürk, the church mosque became a museum, in which worship was forbidden. According to the Encyclopedia of the Ottoman Empire, Atatürk’s decision not only turned Hagia Sophia into ‘an artifact of the past’ but rendered it ‘a site of memory instead of … a symbol of lived religious experience.’

Now, however, there is a campaign to turn Hagia Sofia back into a mosque, a campaign backed by, among others, the Turkish Deputy Prime Minister Bülent Arınç, a member of the ruling AKP party. After Pope Francis recently referred to the Armenian genocide, a genocide that Turkey refuses to acknowledge, the Mufti of Ankara, Mefail Hızlı insisted that ‘the pope’s remarks will only accelerate the process for Hagia Sophia to be re-opened for Muslim worship’. For many Christians, that would be sacrilege. Greece, which sees the monument as part of its own historical heritage, has condemned the idea as ‘an insult to the religious sensibilities of millions of Christians’.

Two cities at opposite ends of Europe, two buildings symbolic of the continent’s complex history, two debates that expose the fractious character of contemporary European identity. It is that history and that debate that I want to explore today.

For many in Europe, Islam is undermining the very fabric of the continent’s Christian identity. When Anders Behring Breivik launched his murderous rampage in Oslo and Utoøya, he saw it as the first shots in a war in defence of Christian Europe; not a religious war but a cultural one. ‘Myself and many more like me’, he wrote in his online manifesto, ‘do not necessarily have a personal relationship with Jesus Christ and God. We do however believe in Christianity as a cultural, social, identity and moral platform.’

Few but the most psychopathic have any sympathy for Breivik’s homicidal frenzy. Most Christians have rejected Breivik’s claim to be one of them. Yet the idea that Christianity is a ‘cultural, social, identity and moral platform’ that provides the underpinnings of ‘Western civilization’ and that ‘Christian Europe’ is under threat finds a widespread hearing.

Europe, Cardinal Miloslav Vlk, the Archbishop of Prague has argued , ‘has denied its Christian roots from which it has risen and which could give it the strength to fend off the danger that it will be conquered by Muslims, which is actually happening gradually’:

At the end of the Middle Ages and in the early modern age, Islam failed to conquer Europe with arms. The Christians beat them then. Today, when the fighting is done with spiritual weapons which Europe lacks while Muslims are perfectly armed, the fall of Europe is looming.

It is not just believers who talk in such alarmist language. It is an argument being increasingly heard from non-believers and non-Christians too. The late Oriana Fallaci, the Italian writer who described herself as a ‘Christian atheist’, insisted that only Christianity provided Europe with a cultural and intellectual bulwark against Islam. The British historian Niall Ferguson calls himself ‘an incurable atheist’. Yet he is alarmed by ‘The erosion of Christianity’ because it ‘makes more difficult ‘the transmission… of ethical values between generations’. Melanie Phillips, a non-believing Jew, and leading writer and broadcaster on both sides of the Atlantic, argues in her book The World Turned Upside Down that ‘Christianity is under direct and unremitting cultural assault from those who want to destroy the bedrock values of Western civilization.

While many in Europe worry about the erosion of the values of Christendom, many Muslims fear the same of Islam. The terrible destruction by the Taliban of the Buddhas of Bamiyan, by the Islamic State of the churches of Mosul and the ancient Assyrian city of Nimrud, of Malian Islamists of the library of Timbuktu, which held an astonishing archive of early Islamic and Christian history, speaks to the desire to erase a past deemed unacceptable, to create an Islam of myth rather than of history. Most Muslims no more support the Taliban or IS than most Christians support Anders Behring Breivik. But just as Breivik’s fears about the loss of identity is echoed much more widely, so it is with many Muslims. The debate over Hagia Sophia and that over the mosque cathedral in Cordoba are both expressions of this.

In his book The Fear of Barbarians, the philosopher Tzvetan Todorov observes that the world today is structured not so much by ideology as by emotion, and in particular the emotions of fear and resentment. In the West, he argues, public attitudes and political policy have been shaped by fear of terrorism, of immigration and of the ‘Other’, and resentment about the loss of power and prestige abroad, and of the supposed erosion of ‘Western’ culture at home. Among Muslims, there exists a sense of what Todorov calls ‘humiliation, real or imaginary’ which has bred resentment towards Europe and the United States, which are ‘held responsible for private misery and public powerlessness.’

Identity rather than ideology has become the key shaper of social consciousness. And in this process, people are increasingly drawn to imagining a world torn apart by a ‘clash of civilizations’.

First coined by the historian Bernard Lewis, the idea of ‘clash of civilizations’ was popularized in the 1990s by the American political scientist Samuel Huntington. The conflicts that had convulsed Europe over the past centuries, Huntington wrote, from the wars of religion between Protestants and Catholics to the Cold War, were all ‘conflicts within Western civilization’. The ‘battle lines of the future’, on the other hand, would be between civilizations. Such struggles would be ‘far more fundamental’ than any war unleashed by ‘differences among political ideologies and political regimes’. The ‘people of different civilizations have different views on the relations between God and man, the individual and the group, the citizen and the state, parents and children, husband and wife, as well as differing views of the relative importance of rights and responsibilities, liberty and authority, equality and hierarchy’.

Huntingdon identified a number of distinct civilizations, including Confucian, Japanese, Buddhist, Hindu, Orthodox, Latin American and African. The primary struggle would, he thought, be between the Christian West and the Islamic East. Coming into vogue in the decade before 9/11, it has, for many, come to define the decade after. It has become a means through which to express the sense of fear and resentment of which Todorov writes, a way of understanding notions of belongingness and enmity in emotional rather than ideological terms.

Civilizations are not, however, self-enclosed entities. What we call ‘civilizations’ are complex constructions. They are ‘civilizations’ precisely because they are porous, fluid, open to wider influences. They borrow, steal and remake each others’ jewels. The more frentic the borrowing, the more fertile the ground for innovation. The great civilizations developed primarily in those areas where different a variety of different peoples, cultures, faiths could meet. One reason that the Eastern Mediterranean was such a forge for civilizations – Phoenicia, Israel, Babylon, Egypt, Persia, Greece, Byzantium and many others – was that it was also a furnace for intellectual and cultural melding.

Not only are civilizations culturally and conceptually diverse, but ideas and concepts are historically malleable. Those who talk of a Christian bedrock of Europe imagine that there is a lineage that runs from contemporary European values back through history to the origins of Christianity. There is no such thread. There are many threads that link the present to the past; many breaks in these threads; and many new threads created through history.

The meanings of many of the values which modern Europe supposedly draws from Christianity – such as equality, universality and tolerance – are significantly different today than they were 500, 1000 or 2000 years ago, within the Christian tradition, let alone beyond it. What today we describe as ‘Western’ values would leave many of the key figures of Christianity, Augustine and Aquinas, Dante and Erasmus, for instance, bewildered. On the other hand, Aquinas and Dante would have understood the Islamic values of Muslim philosophers such Ibn Sina or Ibn Rushd, and certainly better than they would those of philosophers who have shaped contemporary thinking such as, say, Bentham or Mill, Nietzsche or Sartre, Heidegger or Moore.

There is, in other words, no single set of European values that transcends history in opposition to Islamic values. Nor is there a single set of Islamic values that transcend history. What I want to talk about here is the historical complexity both of what we call ‘Christian Europe’ and of Islam, and of the relationship between Christianity and Islam.

Christianity has certainly been the crucible within which the intellectual and political cultures of Western Europe have developed over the past two millennia. But the philosophical, cultural and moral roots of modern Europe are, in fact, highly diverse.

Few people question the importance of Greece to the modern Western tradition. Yet, the story of ancient Greece has somehow been folded into the Christian tradition. This is problematic for two reasons. First, has always been a fraught relationship between Greek and Christian thought. And second because much Greek philosophy came to Europe (and indeed to Christianity) via Islam.

The starting point of Greek philosophy, and certainly of moral philosophy, is usually seen as Socrates. Prior to the Socratic revolution, the moral framework within which people lived was rarely explicitly established but more often intuitively grasped through stories and myths. Homer’s Iliad and the Odyssey are good examples. These were in many ways foundational texts for Ancient Greek culture. They were also means by which ancient Greeks made sense of their moral lives. They were, however, works of poetry not of philosophy. Homer articulated no comprehensive philosophical framework, but imagined a story within which his readers, and listeners, found both an explicit history and an implicit morality

What was important about Socrates was the claim that ideas about what constituted a virtuous act or a good life were not implicitly crafted, and intuitively grasped, through the narrative of myth, but explicitly established through rational argument. This was the emergence of philosophy as distinct from poetry and mythology.

It is worth adding that the transformation of Greek thought was not a unique event. There were similar changes throughout world, in Persia, India and China, with the emergence of thinkers such Confucius, Mo Tzu and the Buddha; Confucius was born a century before Socrates, the Buddha about half a century before, Mo Tzu around the same time. For all of them, the starting point of moral discussion was the idea of humans as rational beings; all, to a greater or lesser degree, looked to reason as a means of finding answers in a world they saw as constrained by fate.

Ancient Greece, even though we rarely think of it in this way, was a deeply religious society. It was a world in which gods constantly intervened in human life, a world constrained by fate. A world in which Socrates was sentenced to death by an Athenian jury for supposedly rejecting recognized gods, introducing new divinities and corrupting the youth.

But the religious sensibility of the Ancient Greeks was very different from that of Christians later, or of the modern world. The very idea of a world constrained by fate, and of ever-interfering gods led the Greeks to develop a very worldly, and non-religious, moral philosophy.

The gods of the Ancients were not wise and judicious like the later gods of Judaism, Christianity and Islam. They were, rather, capricious, vain, vicious, deceitful and immoral. They were also immensely powerful. Fate was seen as a social reality and there was no evading it. Human life was defined by the inevitability of death, the universality of sorrow and suffering, the tragedy of being answerable for one’s actions and yet imprisoned by fate.

With tragedy, however, came dignity. Ancient gods acted according to whim; only humans were truly accountable for their actions. Human life was framed by the gods and yet humans could not rely upon them. They had to depend upon their own wit and resources. It was human reason and human morality that imposed order upon an unpredictable world, and carved out dignity and honour within it.

Monotheism – Judaism, Christianity and Islam – introduced a very different vision of human nature and character of moral thinking. While the three monotheistic faith were significantly different, they were also significantly different from the pre-monotheistic faiths, and in similar ways. For the Ancients, there were hundreds of gods, but all were constrained by the structure of reality. For the monotheists there was but one God, all-powerful and constrained by nothing. He could act as He chose.

Ancient Gods were very human – in fact all too human. The Monotheistic God was terrifying divine. Monotheism created a chasm between human world and the divine world as had not existed before.

Monotheism made humans both greater and lesser than they had been before. Humans had been created by God in His image, a notion that helped monotheistic thinkers enlarge the meaning of ‘humanity’. The dignity of the individual, in principle at least, derived not from his or her participation in a specific community but through their God-created nature.

Yet what God giveth with one hand, he taketh away with the other. Humans were now seen as weak, corrupt, flawed and broken. Where the Ancient Greeks had seen humans as carving out a space for dignity and honour within an unpredictable universe, and in the face of capricious and often immoral gods, Christians insisted that humans could not be good on their own but only through God.

At the heart of Christian belief is the Fall and in Original Sin, the insistence that all humans are tainted by Adam and Eve’s disobedience of God in eating of the fruit of the Tree of Knowledge. It is impossible for humans to do good on their own account, because the Fall has degraded both their moral capacity and their willpower. Only through God’s grace can humans achieve salvation.

The fundamentally different view of human nature, and of the relationship between the human and the divine, meant that what we now think of as the Judeo-Christian tradition has been created as much despite the efforts of the Christian Church as because of them. ‘What is there in common between Athens and Jerusalem?’, asked Tertullian, the first significant theologian to write in Latin. So preoccupied were devout Christians with the demands of the next world that to study nature or history or philosophy for its own sake seemed to them almost perverse. ‘Let Christians prefer the simplicity of our faith to the demonstrations of human reason’, insisted Basil of Caesarea, an influential fourth century theologian and monastic. ‘For to spend much time on research about the essence of things would not serve the edification of the church.’ Augustine, who with Thomas Aquinas is the greatest of all Christian philosophers, came to see uninhibited curiosity as an evil, in his Confessions condemning as a ‘disease’ the yearning to discover ‘the hidden powers of nature… which to know profits not’.

I will return to the question of the Christian relationship to the Greek philosophical tradition shortly. But first, a few words about its relationship to the other ancient European civilization: Rome.

It is often said that from Rome came the Western attachment to the rule of law. Roman law, as the legal historian Paul Koschaker has put it, is the ‘bond of law by which so often the West is held together’. Or in the words of the American economist and historian Jeffrey Sachs,

The basic legal institutions of European civilization emerged in a specific cultural environment, that of the early Roman Republic. Roman law grew into a complex procedural system administered by trained jurists in the Roman Empire, the Byzantine Empire, and later European monarchies.

I do not have the time to delve too deeply into this issue today. But, how much modern notions of the rule of law are indebted to Roman concepts is a matter of debate. As Sachs himself observes, ‘Because it never imposed constitutional restraints on the executive’, Roman law ‘did not ensure the Rule of Law in the modern sense.’ So the famous Napoleonic code, often regarded as a modern version of Roman law, guaranteed, in Sach’s words, ‘equality before the law and protected private property rights in the tradition of Roman law, but they did not infringe on the prerogatives of the emperor and his spies, censors, and secret police.’ The idea that the government itself was bound by law is a modern innovation, and again shows how modern concepts have a complex relationship to similar concepts in the ancient world.

What Rome did provide for Christianity was power. Early Christian communities were small, diverse and isolated. Christians faced great hostility from the communities in which they were embedded. Within four centiries, however, Christianity had moved from being a fringe, persecuted faith to one of power and authority, the official religion of the Roman Empire.

The key figure was Emperor Constantine who converted to Christianity and became a patron for the faith, supporting it financially, promoting Christians to high office, and building an extraordinary number of basilicas. When Constantine transformed Byzantium, an ancient Greek town on the Bosphorus, into his new imperial capital, Constantinople, he turned it into a Christian city, building churches within the city walls but no pagan temples.

Over time, as the Roman empire divided into two, so did the Christian faith, between the eastern Church, based in Constantinople, and the Western Church, rooted in Rome. Today we imagine the Western Church as Christianity’s intellectual and spiritual powerhouse, and often regard the Eastern Orthodox faith as obscure and backward. But in the early Middle Ages, the eastern half of the Empire was more prosperous than the west, its political structure more stable, its intellectual achievements more entrenched, its cultural sophistication more polished.

In the west, tribal attacks tore at the very fabric of Roman life. Cities rumbled, technology regressed, agriculture decayed, populations plummeted, trade declined. The very precariousness of life in the west was, paradoxically, the making of Christianity. As the authority of imperial institutions collapsed, the Church was left as almost the only body capable of maintaining some semblance of social order within the boundaries of the disintegrating empire. Imperial collapse also left the clergy as the sole literate class in the Western world and the Church as the lone patron of knowledge and the arts. But if the Church kept alive elements of a learned culture, Church leaders, were as we have seen ambiguous about the merits of pagan knowledge.

The most significant casualty of the Christianising of learning was Aristotle whose empirical, this-worldly approach to knowledge was most at odds with the dictates of faith. In the Name of the Rose, Umberto Eco’s beguiling philosophical whodunit, the Franciscan friar William of Baskerville and his novice, Adso of Melk, investigate a series of murders at a Benedictine monastery in Northern Italy.  They  uncover a plot to keep hidden a single book in the abbey’s library, the greatest in Christendom. In the novel’s denouement, amidst the ruins of a burning library, William asks the blind librarian Jorge of Burgos why he has devoted his life to protecting the world from any knowledge of this single work. ‘Because it was by the Philosopher’, replies Jorge. ‘Every book by that man has destroyed a part of the learning that Christianity had accumulated over the centuries.’ The Philosopher was Aristotle. Despite the Book of Genesis revealing ‘what has to be known about the composition of the cosmos’, Jorge bemoans, ‘it sufficed to rediscover the Physics of the Philosopher to have the universe reconceived in terms of dull and slimy matter.’

At the beginning of the twelfth century, the only works of Aristotle known in Latin were the Categories and De Interpretatione. By the end of the century virtually all his works had been translated into Latin. How did theologians and scholars in Western Europe find their way back to Greek thought? Primarily through the Muslim Empire.

History books used to talk of the ‘Dark Ages’, the period between the fall of the Roman empire and the rebirth of leaning in the Renaissance. Few historians would use that term today, recognizing it as a self-serving phrase invented by Petrarch in the fourteenth century and employed by later Renaissance thinkers to elevate the intellectual standing of their own era. Nevertheless, there can be little doubt that there was, through the disintegration and collapse of the Roman Empire, a decline in the culture of learning in Western Europe. While the accretion of knowledge and learning did not disappear, scholarship was of a different quality to that which had flourished previously in Greek and Hellenistic cultures, on the one side, and would again in the European cultures of the later Middle Ages.

There was in this period, however, an intellectual tradition as lustrous as that of Ancient Athens before or Renaissance Florence after. Not in Christian Europe but in the Islamic Empire. Centred first in Baghdad and then in Córdoba, Arab philosophy and science played a critical role not just in preserving the gains of the Greeks but in genuinely expanding the boundaries of knowledge, both in philosophy and in science.

Before I take up the story of what the Judeo-Christian tradition owes to Islam, let me explore the many sources of the Islamic world itself. You only have to open the Qur’an to recognize how much Islam owes to Christianity and Judaism. The very stories of the Qu’ran, from Adam and Eve to Jesus himself, draw upon the Jewish and Christian holy texts, though clearly the Qur’an retells these stories in a distinctive fashion.

There was nothing about Muhammad’s monotheism that would have surprised or scandalized Arabs. The Arabian peninsula was home to significant Jewish populations, whose presence can be traced back to the Babylonian exile from Israel enforced by Nebuchadnezzar in the sixth century BCE. Indeed, so close was the relationship between Jews and pre-Islamic Arabs that Arabs considered themselves to be descendants of Abraham, or Ibrahim as they knew him. Even before Muhammad, there had been a tradition of Arab prophets, called hanifs, who preached the virtues of a single God.

But it was after the death of Muhammad that we can truly see the debt of Islam to a variety of different cultures and civilizations. A series of wars in the seventh and eighth centuries created a vast new empire. Barbarian invasion, agricultural collapse, plague and war had all sapped the strength of the old Mediterranean world.

Barely a decade after Muhammad’s death, the whole of the Arabian Peninsula, Mesopotamia, Persia, Syria and Egypt had been conquered. By the early eighth century, the Muslim Empire stretched from Sindh in the East to Iberia in the West.

The new empire had within its borders a treasure house of philosophical, scientific and religious texts, mainly Greek and Persian. These were soon translated into Arabic. The Arab world discovered Plato and Aristotle, Euclid and Ptolemy. Much of the translation was not by Muslims but by Christian scholars, particularly in Syria. Just as later the work of Muslim philosophers such as Ibn Rushd would transform the Christian and Judaic traditions, but largely be ignored within Islam, so the work of Syriac Christian translators transformed the intellectual standing of the Islamic empire, at a time when learning in Christian Europe was languishing.

The acquisition by Arabs of the philosophical jewels of the Greek and Persian worlds helped transform the intellectual culture of the new empire. In the mid-eighth century, the Caliph al-Mansur built the new city of Baghdad to be his imperial capital. And here his great grandson, the Caliph Al-Ma’mun, created the ‘House of Wisdom’, a celebrated library and centre for scholarship that turned Baghdad into the world’s greatest intellectual centre of its time.

By the second half of the tenth century all the great works of Greek and Persian had been translated and studied. Now began a new period of original Arabic scholarship. Over the next three centuries there was in the Muslim world a remarkable flourishing of science and learning. Arab scholars revolutionized astronomy, invented algebra, helped develop the modern decimal number system, established the basis of optics, and set the ground rules of cryptography. But perhaps more important than the science was the philosophy.

The translation into Arabic of Aristotle, Plato and other Greek philosophers helped transform Islamic thinking. In particular, it helped create what is sometimes called the Rationalist tradition, a tradition that began with the Mu’tazilites in the eighth century and culminated with the two greatest of Muslim philosophers, Ibn Sina and Ibn Rush’d, some four hundred years later.

The Rationalists saw learning as an ethical duty. They took from the Greeks not just their spirit of rational inquiry but also their faith in the almost boundless power of the human intellect. Most were deeply pious, and accepted the Qur’an as the word of God. But they challenged the idea that religious truths could be accessed only through divine revelation, insisting that reason alone would suffice. Most insisted, too, that all theological arguments must adhere to the principles of rational thought. Even the interpretation of the Qur’an and the Sunna were, in Rationalist eyes, subordinate to human reason.

By the time the greatest of these philosophers, indeed the greatest Muslim philosopher, Ibn Rushd, was publishing his translations of, and commentaries on, Aristotle, the Rationalist tradition was already on the wane. Islam came eventually to define itself not through rationalism, but through mysticism on the one hand – the Sufi traditions – and, on the other, a more literal understanding of Revelation, such as that embodied in the Sunni traditions.

The tradition of Muslim Rationalism is these days barely remembered in the West. Yet its importance and influence, not least on the ‘Judeo-Christian’ tradition, is difficult to overstate. It was through Ibn Rushd that West European philosophers rediscovered their Aristotle, and his commentaries shaped the thinking of a galaxy of thinkers from Moses Maimonides to Thomas Aquinas. And Córdoba, Ibn Rush’d’s home, became a principal meeting point of Islam and Christianity, a centre through which Christian scholars came to access not simply Islamic thinking, but to rediscover Greek philosophy too.

While today we may have forgotten the importance of Muslim philosophers, Christians of the time certainly recognized it. In The Divine Comedy, Dante places Ibn Rushd with the great pagan philosophers whose spirits dwell not in Hell but in Limbo ‘the place that favor owes to fame’. One of Raphael’s most famous paintings, The School of Athens, is a fresco on the walls of the Apostolic Palace in the Vatican, depicting the world’s great philosophers. Among the pantheon of celebrated Greek philosophers including Aristotle, Plato, Socrates, Pythagoras and Diogenes stands Ibn Rushd.

It was not just Greek philosophers that shaped Islamic thinking. From Persia to India to China, civilizations across the globe became sources for Islamic culture and learning. India, in particular, with the establishment of Mughal Empire in the sixteenth century indelibly shaped Islam. When we think of the Muslim world today, we usually think of the Middle East. But the largest Muslim communities are in Asia – in Indonesia, Bangladesh, India, China – and here Islam draws upon a multitude of cultural and religious sources.

Today, there is a tendency to think of Islam as walled-in, insular, hostile to reason and freethinking. Much of the Islamic world came to be that way. But the fact remains that the scholarship of the golden age of Islamic thinking helped lay the foundations for the European Renaissance and the Scientific Revolution. Neither happened in the Muslim world. But without the Muslim world, it is possible that neither may have happened, at least in the form they did.

So, finally, let me turn finally to the world created by those revolutions – by the Renaissance, the Scientific Revolution, and, most importantly, the Enlightenment. What are now often called ‘Western values’ – democracy, equality, toleration, freedom of speech, and so on – are the products largely of the Enlightenment and of the post-Enlightenment world. Such values are, of course, not ‘Western’ in any essential sense but are universal; they are ‘Western’ only through an accident of geography and history.

A complex debate has arisen about the relationship between the Enlightenment and the Christian tradition.  As the notion of the Christian tradition and of ‘Western civilization’ have become fused, and as the Enlightenment has come to be seen as embodying Western values, so some have tried to co-opt the Enlightenment into the Christian tradition. The Enlightenment ideas of tolerance, equality and universalism, they argue, derive from the reworking of notions already established within the Christian tradition. Others, more ambiguous about the legacy of the Enlightenment, argue that true liberal, democratic values are Christian and that the radicalism and secularism of the Enlightenment has only helped undermine such values.

Both views are wrong. For a start, the historical origins of many of these ideas lie, as we have seen, outside the Christian tradition. It is as apt to describe a concept such as equality or universalism as Greek as it is to be describe it as Christian. In truth, though, contemporary ideas of equality or universality are neither Greek nor Christian. Whatever their historical origins, they have become peculiarly modern concepts, the product of the specific social, political and intellectual currents of the modern world.

Not only are ‘Christian values’ and ‘Islamic values’ more complex, and with a more convoluted history than contemporary narratives suggest, so is the relationship between Enlightenment ideas and religious belief. There were, in fact, as historian Jonathan Israel pointed out in his wonderful three-part history of the period, Radical Enlightenment, Enlightenment Contested and Democratic Enlightenment, two Enlightenments. The mainstream Enlightenment of Kant, Locke, Voltaire and Hume is the one of which we know and which provides the public face of the Enlightenment. But it was the Radical Enlightenment, shaped by lesser-known figures such as d’Holbach, Diderot, Condorcet and, in particular, Spinoza that provided the Enlightenment’s heart and soul.

The two Enlightenments, Israel argues,divided on the question of whether reason reigned supreme in human affairs, as the radicals insisted, or whether reason had to be limited by faith and tradition – the view of the mainstream. The mainstream, Israel writes, ‘aspired to conquer ignorance and superstition, establish ideas and revolutionise ideas, education and attitudes by means of philosophy but in such a way as to preserve and safeguard what were judged as essential elements of the older structures, offering a viable synthesis of old and new, of reason and faith.’ By contrast, the Radical Enlightenment ‘rejected all compromise with the past and sought to sweep away existing structures entirely’.

This distinction was, Israel suggests, to shape the attitudes of the two sides to a whole host of social and political issues such as equality, democracy and colonialism. The attempt of the mainstream to marry traditional theology to the new philosophy, Israel suggests, constrained its critique of old social forms and beliefs.

The Radicals, on the other hand, were driven to pursue their ideas of equality and democracy to their logical conclusions because, having broken with traditional concepts of a God-ordained order, there was, in Israel’s words, no ‘meaningful alternative to grounding morality, political and social order on a systematic radical egalitarianism extending across all frontiers, class barriers and horizons.’

The moderate mainstream was overwhelmingly dominant in terms of support, official approval and prestige. But in a deeper sense, and in the long run, it proved less important than the radical strand. As Israel shows the ‘package of basic values’ that defines modernity – toleration, personal freedom, democracy, racial equality, sexual emancipation and the universal right to knowledge – derive principally from the claims of the Radical Enlightenment and has been profoundly shaped by radicals’ challenge to the Christian tradition.

To argue all this is not to deny the distinctive character of the Christian tradition (or traditions), nor the important role that Christianity has played in incubating what we now call ‘Western’ thought, nor yet the significant philosophical advances made within that tradition. But the Christian tradition, and Christian Europe, just like the Islamic tradition, and the Islamic world, is better thought of as a chimera than as a pure-bred beast.  The history of both Christianity and Islam, their relationship to each other and to other traditions, and the relationship between Christian and Islamic values and those of modern, liberal, secular societies is far more complex than so much contemporary debate allows.

There is much more that I could, and would like to, say about all this. But time has run out. So, let me finish by returning to Córdoba and Istanbul, to the mosque cathedrals in both cities. In these two buildings, two of the greatest architectural treasures of the world, in their stones and slates and marble and gold, in their pillars and arches and windows and mosaics, can be glimpsed the complexity of European history, of the Christian tradition, of the story of Islam. In many of the debates that surround these buildings can be heard the attempts to rewrite that history, to cleanse our stories of all complexity, to discover a myth to impose upon our lives.

It is up to us whether we chose to listen to the stories told by the buildings or by the myths being imposed upon them. Which story we listen to will colour our past. It will also shape all our futures.

The paintings are, from top down, David Hockney’s ‘Andalucia, Mosques, Cardova’; Roger Hayward, ‘Watercolor painting of the Hagia Sophia’; ‘Madonna and child’, an apse mosaic in the Hagia Sophia; Pauwel Casteel’s ‘Battle of Vienna’; Giovanni Bellini’s ‘St Mark Preaching in Alexandria’; Antonio del Pollaiolo’s ‘Hercules and the Hydra’; Cigoli’s ‘Ecce Homo’; Masaccio’s ‘Expulsion of Adam and Eve from Eden’; Giovanni Paolo Panini’s The Interior of the Pantheon, Rome’; Rembrandt’s ‘Aristotle with a Bust of Homer’; 13th century Arabic translation of ‘Material Medica’; Raphael’s ‘School of Athens’;  Jacques Louis David’s ‘Le Serment de Jeu de Paume’; Eugene Delacros’ ‘Liberty Leading the People’.