Current wisdom would have it that 'five centuries of peaceful co-existence' between Muslims and Christians were brought to an end by 'political events and an imperial-papal power play,' that was to lead to a centuries-long series of so-called "holy-wars" that pitted Christendom against Islam, and left an enduring legacy of misunderstanding and mistrust.'
A school textbook, Humanities Alive 2, for Year 8 students in the Australian State of Victoria, carries the anti-Christian/anti Western argument further:
Those who destroyed the World Trade Centre are regarded as terrorists. Might it be fair to say that the Crusaders who attacked the Muslim inhabitants of Jerusalem were also terrorists?
Muhammad died in Medina on June 8, 632 AD. The first of the eight Crusades to free the Holy Places in Palestine from Muslim control, and offer safe passage to the Holy Land for Christian pilgrims, was called only in 1095. At the risk of sounding pedantic, the period in question is not 'five centuries,' but four-hundred and sixty-three years; and those years, we contend, were not characterized by 'peaceful coexistence'.
Islam's attack on Christianity
For the Christian states bordering the Mediterranean, it was a four-hundred and sixty-three year period of regular, disorganized [and occasionally organized] bloody incursions by Muslim mainly Arab and Berber land and sea forces. These came intent on booty - gold, silver, precious stones and slaves - on destroying churches, convents and shrines of the 'infidels,' and on the spread of politico-religious Islam throughout Europe from their bases in the Mediterranean and the Adriatic.
At the time of Muhammad's death there were flourishing Christian and Jewish communities in Arabia, and throughout the major centres of the Persian Empire. The whole of the Mediterranean world on its European, Asian and African sides, was predominantly Christian.
It had taken only a few years for Muslim tribesmen from Arabia, inspired by Muhammad's revelations and example, to invade the Eastern Roman or Byzantine Empire whose emperors devoted more time to religious disputation than to defending their empire. In 633 Mesopotamia fell. After a few years the entire Persian Empire fell to the marauding Arab tribesmen who drove the young Persian emperor Yazdagird into the farthest reaches of his empire, to Sogdiana [Uzbekistan], where he was eventually murdered by his Tartar bodyguard in a miller's hut.
Damascus fell in 635, and Jerusalem capitulated five years after Muhammad died, in February 638.
The fall of Alexandria in 643 sounded the death knell of more than thousand years of Hellenic civilization that once enriched the whole of the Near East with its scholarship and culture. Henri Daniel-Rops claims that from the point of view of the history of civilization, Alexandria's fall was as significant as the fall of Constantinople to the Turks eight-hundred years later.
Cyprus fell in 648-9 and Rhodes in 653. By 698 the whole of North Africa was lost.
Less than eighty years after Muhammad's death, in 711, Muslims from Tangiers poured across the 13 km wide strait of Gibraltar into Spain. By 721 this Arab-Berber horde had overthrown the ruling Catholic Visigoths and, with the fall of Saragossa, set their sights on southern France.
By 720 Narbonne had fallen. Bordeaux was stormed and its churches burnt down by 'Abd al-Rahman ibn Abdullah al-Ghafiqi in early spring 732. A basilica outside the walls of Poitiers was razed, and 'Abd al-Rahman headed for Tours which held the body of St Martin [who died in 397] apostle and patron saint of the Franks.
He was to be defeated and killed by Charles Martel and his Frankish army on a Saturday in October, 732, one hundred years after Muhammad's death, on the road from Poitiers to Tours a defeat that was hailed by Gibbon and others as decisive in turning back the Muslim tide from Europe.
Attacks on France, however, continued, and in 734 Avignon was captured by an Arab force. Lyons was sacked in 743. It wasn't until 759 that the Arabs were driven out of Narbonne. Marseilles was plundered by them in 838.
Muslim incursions into Italy had been a feature of life from the early 800s. The islands of Ponza [off Gaeta] and Ischia [off Naples] had been plundered, and then, in 813 Civitavecchia, the port of Rome, whose harbour had been constructed by Trajan, was sacked by the Arabs.
In 826 the island of Crete fell to Muslim forces which retained it as their base until 961. From around 827 they then began nibbling at Sicily. They captured Messina and controlled the Strait of Messina by 842, and finally took the whole island in 859, after Enna fell to them.
In 836 the Neapolitans self-interestedly invited the Muslim forces to help them against the Lombards and set the stage for more than a century of Muslims raids along the Adriatic, involving the destruction of Ancona, and Muslim progress as far as the mouth of the Po. 'Saracen Towers' south of Naples, built in the ninth century to warn locals of the approach of Arab fleets from Sicily and Africa still charm visitors to the Neapolitan coast.
Bari, now home to the relics of St Nicholas of Myra, the original 'Father Christmas,' fell to Khalfun, a Berber chieftan, by another act of treachery in 840. From 853-871 the notorious Muslim brigand al- Mufarraj bin Sallam, and his successor, another Berber named Sawdan, controlled all the coast from Bari down to Reggio Calabria, and terrorized Southern Italy. They even plundered the Abbey of St Michael on Mt Gargano. They claimed the title of Emir, and independence of the Emir in Palermo.
Sacking of St Peter's
Naples herself had to beat off a Muslim attack in 837. But in 846 Rome was not to be so fortunate. On August 23rd 846, Arab squadrons from Africa arrived at Ostia, at the Tiber's mouth. There were 73 ships. The Saracen force numbered 11,000 warriors, with 500 horses.
The most revered Christian shrines outside the Holy Land, the tombs of Sts Peter and Paul, were desecrated and their respective Basilicas were sacked, as was the Lateran Basilica along with numerous other churches and public buildings.
The very altar over the body of St Peter was smashed to pieces, and the great door of St Peter's Basilica was stripped of its silver plates. Romans were desolated and Christendom was shocked at the barbarism of the Muslim forces.
Three years later Pope Leo IV [847-855] formed an alliance with Naples, Amalfi and Gaeta, and when a Saracen fleet again appeared at the mouth of the Tiber in 849, the Papal fleet joined forces with its allies and they repelled the Muslim fleet which turned, and ran into a violent wind-storm that destroyed it, like Pharaoh's army long before.
Survivors were brought to Rome and put to work helping to build the Leonine Wall around the Vatican. Twelve feet thick, nearly forty feet in height and defended by forty-four towers, most of this wall, and two of the round towers, can be seen still by visitors to the Vatican. These defensive walls were finished and blessed by Pope Leo IV in 852.
Taranto in Apulia was conquered by Arab forces in 846. They held it until 880.
In 870 Malta was captured by the Muslims. In 871 Bari, the Saracens' capital on mainland Italy, was recaptured from the Muslims by Emperor Louis II, who in 872 was to defeat a Saracen fleet off Capua.. Continuue Reading Here...
 John Esposito, Islam: the Straight Path, 3rd ed. OUP, 1998, p. 58.
 See 'Civilizing influence of previous wars fought between East and West', The Weekend Australian, March 18-19, 2006.
 This article restricts itself to a brief discussion of these claims and counter claims. We plan future articles that will discuss other controverted issues like the collaboration, in the initial phase of Islamic expansionism after the death of Muhammad, with Muslim military forces, by Christians and others, for political and sometimes religious reasons. We will also look at the claim that the Crusades were anti-Islamic, put relations between the Crusaders and the Byzantines, and the sacking of Jerusalem and Constantinople in context. We will consider the degree to which ongoing anti-Catholic polemic since the 16th century has now become a weapon in the hands of radical Islamists.
 The Church in the Dark Ages, J.M. Dent and Sons, London, 1959, p.336.
 The term 'Saracen' is sometimes mistakenly derived from the Arabic Sharqi or 'Easterner'. St Jerome considered it to be the name the Arabs gave themselves, deriving their origins from Sarah, Abraham's free wife, rather than from Hagar, his slave. In many of the sources we have used, the term 'Agareni', or'Hagarines,' is found.
 Letter from Adelbert, Marquis of Tuscany and protector of the Papal territory of Corsica, to Pope Sergius II in Liber Pontificalis, n.xliv, ed. Farnesiana.