Islam Watch has a good article entitled Europe’s Dark Age and Islam’s Golden Age: Two Facets of The Same Fiction?, which discusses the content of the book on the same subject, entitled Holy Warriors.

In the twentieth century, a whole  new body of evidence became available to historians; evidence  unavailable to previous generations of scholars: The evidence of   archaeology. And what archaeology  tells us has been devastating to the  traditional view…..

On the word of the written histories, then, archaeologists expected to find, from Spain to eastern Iran, a flourishing and vibrant culture. An Islamic world of enormous cities endowed with all the wealth of antiquity and the plunder gathered in the Muslim wars of conquest. They hoped to find palaces, public baths, universities and mosques; all richly decorated with marble, ceramic and carved stone.

In fact, they found nothing of the sort.

For a more accurate rendition of history that isn’t colored by the anti-Catholic enlightenment historians or the Muslims trying to pretend that their faith has contributed to humanity, see How Christianity changed the world and The biblical origins of science.

Regarding the decline of Classical Civilization, it turns out it was not the Barbarians or the Christians that killed it, but the Islamic Arabs:

One of the most enduring problems of history is the decline of Classical Civilization. How was it that the civilization of Greece  and Rome, which had endured almost a thousand years, a civilization which prized learning, science and reason, gave way to the world of the Medieval; an age which saw, for a while, the almost complete disappearance of the rationalist spirit of  Greece and Rome? The traditional view was that after their  seizure of Italy in the fifth century, the Barbarian tribes of  Germany and Scythia had reduced Europe to an economic and cultural wasteland, initiating a Dark Age, which was to last half a millennium. After the Reformation, another suspect was added to the list: Christianity, or, more accurately, Catholic Christianity. In this view Christianity was corrupted beyond recognition after the time of Constantine and from the fourth  century onwards a power-hungry Church hierarchy, in cahoots with the Imperial authorities, kept the population of Europe in subservience and ignorance, effectively completing the  destructive work of the Barbarians.

In this ground-breaking work, historian John J. O’Neill examines a great variety of evidence from many specialties and reaches an astonishing and novel conclusion: Classical Civilization was not destroyed by Barbarians or by Christians. It survived intact into the early seventh century. The Vandals and Goths who  seized the Western Empire in the fifth century had become  completely romanized by the start of the sixth century. Artistic and intellectual life flourished, as did the economy and the cities built earlier under the Empire. Yet sometime in the middle of the seventh century everything changed.

Cities were abandoned, literacy plummeted, royal authority declined and local strongmen, or “barons”, seized control of the provinces. The Middle Ages had begun.

Who or what had caused this? As O’Neill notes, by the 1920s Belgian historian Henri Pirenne had located the proverbial “smoking gun”; but it was not in the hands of the Barbarians or the Christians: it was held by those who, even then, it had become fashionable to credit with saving, rather than  destroying, Classical Civilization: the Arabs.

Regarding the “Islamic Golden Age”:

The archaeological non-appearance of the Islamic Golden Age is surely one of the most remarkable discoveries to come to light in the past century. It has not achieved the sensational  headlines we might expect, for the simple reason that a  non-discovery is of much less interest to the public than a  discovery….

Normally, we find one or two finds attributed to the seventh century, then nothing for three centuries, then a resumption of archaeological material in the mid- or late-tenth century. Take,  for example Egypt, the largest and most populous Islamic country during the Early Middle Ages. The Muslim conquest of the country occurred in 638 or 639, and we should expect the invaders to have begun, almost immediately, using the wealth of the land to begin building numerous and splendid places of worship, but apparently they didn’t. Only two mosques in the whole of Egypt, both in Cairo, are said to date from before the eleventh century: the Amr ibn al-As (641) and the Ahmad ibn Tulun (878). However, the latter building has many features found only in mosques of the eleventh century, so its date of 878 is disputed. Thus, in Egypt, we have a single place of worship, the mosque of Amr ibn al-As, dating from the mid-seventh century, then nothing for another three-and-a-half centuries. Why, in an enormous country with up to, perhaps, five million inhabitants, should the Muslims wait over 300 years before building themselves places of worship?

And it is the same throughout the Islamic world. No matter where we go, from Spain to Iran, there is virtually nothing between circa 650 and 950….

The sheer poverty of these remains makes it clear that the fabulously wealthy Cordoba of the eighth, ninth and early tenth centuries is a myth.