Kaiser Wilhelm in the 1890s placed a bronze wreath on the tomb of Saladin, and it said on the wreath, "From one great emperor to another." I find it more than fitting that during World War I, when T. E. Lawrence was leading his irregulars all over the area, he stole that wreath and it's now in the British War Museum.

It was all nonsense. In fact, Saladin was about as great an emperor as Kaiser Wilhelm was.

What of the sacking of Constantinople, when western Christians who had set out to reclaim the Holy Land decided instead to attack eastern Christians? This is often taken as a classic example of the irrationality and ultra-violence of the Crusaders.

It seems to be pretty clear that, through about four crusades, the Byzantines had betrayed the westerners. In the First Crusade, they were supposed to send their army along, and they did not. They were supposed to supply the knights, and they did not. They tried to make separate peace agreements, which was virtually treasonous. This went on and on and on.

Eventually, the knights from the west, having backed a faction of the Byzantines, found themselves having been betrayed again and starving outside of Constantinople. So they sacked the city. It's a wonder they didn't do it sooner.

We are sometimes told that Muslims and Muslim societies have a much longer view of history than we do, and the extremists among them, who have perpetrated violence upon the west in the past two decades, see the present struggle as a continuation of the struggle that "began" with the Crusades.

Until about the start of the 20th century, the Muslims didn't even remember there had been Crusades. This is all about 20th-century nationalism. The whole issue was: How did we get so backward? And the Muslims aren't the only ones who made up the myth that it was the westerners who made them so backward. We are told that almost all other parts of the world are backward or were backward because somehow they got exploited by Europe. It's all very well and good -- but it's all nonsense.

There wasn't any discussion about the Crusades until the 20th century, when it became one of the slogans of Arab nationalism. And even then, it was a pretty minor issue until the formation of the state of Israel. That's when suddenly the Crusades became a really big thing with Muslim nationalists. "We can blame the West for everything, including Israel." That may be good politics, but it's rotten history.

By the way, I'm not making this up, either. Again, there is a consensus among historians of the Crusades that there is no record of Muslim concern with the Crusades until the 20th century.

What exactly is the connection with Israel? Israel was established and supported by the West, and the rulers of Islamic nations utilized the rhetoric of the Crusades to rally support against Israel, or distract from their own failures, or what?

All of the above. "The West did it to us. The West took our oil. We would be an advanced civilization, but somehow the West stole it from us. Once upon a time, we were the enlightened people, and it all went away when the Europeans stole it." It does a lot for national pride, but it doesn't do a damn thing for history.

And this ties together with works you've written on how Christian thought laid the groundwork for the development of western civilization, with all its innovations in medicine and science, politics, and so on.

Sure. Let's face it: Christianity was the basis of western civilization. When you look at western civilization and see what it has, it came from Christianity. The notion that somehow western science broke through against the resistance of religion is total nonsense. Without the religious background, there wouldn't be any science, because the fundamental notion that separated the West from everybody else was the notion that God is rational and created a rational universe, so there were rules out there to be discovered.