[T]he 463 years between the death of Muhammed in 632 AD, and the First Crusade in 1095, were extremely dangerous for Christian Europe. Instead of peace there were unrelenting Islamic wars and incursions; Muslim invasions of Spain, Italy, Sicily and Sardinia; raids, seizures, looting of treasure, military occupations that lasted until Saracen forces were forcibly dislodged, sackings of Christian cities including Rome, and desecrations of Christian shrines. And be it noted: all this went on for 463 years before any Christian Crusade in response to these murderous provocations took place.
Sixteen years after the death of Muhammed, in 648 AD, Cyprus was overrun. Rhodes fell in 653, and by 698 AD the whole of North Africa was lost. In 711 Muslims from Tangier crossed into Spain, set their sights on France, and by 720 AD Narbonne had fallen. Bordeaux was stormed and its churches burnt in 732. As Gibbon emphasised, only the resistance at Poitiers of Charles Martel in 732 saved Europe from occupation, and arrested the Muslim tide.
From 800 on, incursions into Italy began. In 846 a Saracen force of 10,000 landed in Ostia, assaulted Rome, and sacked and desecrated the Basilicas of St Peter and St Paul. In 859 they seized the whole of Sicily. After capturing a fortress near Anzio, Muslim forces “plundered the surrounding countryside for forty years”. In southern France at the end of the ninth century they held a base near Toulon from which they ravaged both Provence and Northern Italy, and controlled the passes over the Alps, robbing and murdering pilgrims on their way to Rome. Genoa was attacked in 934 and taken in 935. In 1015 Sardinia was taken, occupied, and held my Muslim forces until 1050.
In 1076 the Seljuk Turkish capture of Jerusalem finally exhausted the patience of Islam’s victims in Christian Europe. Only then were concerted moves begun to drive back the infidel, launch the First Crusade, and retake Jerusalem.
He has much more to say on the subject of religion and violence, all of it interesting. Check out his essay here.