According to this representation, Western Christians were invaders in a peaceful region that was respectful of the different religions — the Holy Land, which back then was part of Syria — using religious motives to disguise imperialist ambitions and economic interests.
But the idea of the crusades emerged, above all, as a reaction to the measures that the Fatimid caliph Hakim bi-Amr Allah took against the Christians of Egypt and Syria. In 1008, al-Hakim outlawed the celebrations of Palm Sunday, and the following year he ordered that Christians be punished and all their property confiscated. In that same year of 1009, he sacked and demolished the church dedicated to Mary in Cairo, and did not prevent the desecration of the Christian sepulchers surrounding it, or the sacking of the city’s other churches. That same year saw what was certainly the most severe episode: the destruction of the Constantinian basilica of the Resurrection in Jerusalem, known as the Holy Sepulcher. The historical records of the time say that he had ordered “to obliterate any symbol of Christian faith, and provide for the removal of every reliquary and object of veneration.” The basilica was then razed, and Ibn Abi Zahir did all he could to demolish the sepulcher of Christ and any trace of it.
That reminded me of this multiple books review in First Things from this past summer. In it, Prof. Thomas Madden applauds what he sees as a turning of the tide in academic research into the Crusades:
As historians of the Crusades begin to present their research to the general reader, the common caricature of these events is finally beginning to dissolve. Unlike most older popular histories on the subject, these new books are fastidious about the facts, and they are less inclined to patronize the past or flatter the modern reader’s prejudices. While their arguments about what motivated the Crusades are sometimes question able, they are never anachronistic—and that alone constitutes an important improvement.
By contrast, see this chapter on the Crusades in Extraordinary Popular Delusions and the Madness of Crowds, by the 19th century skeptic Charles Mackay:
Now what was the grand result of all these struggles? Europe expended millions of her treasures, and the blood of two millions of her children; and a handful of quarrelsome knights retained possession of Palestine for about one hundred years! Even had Christendom retained it to this day, the advantage, if confined to that, would have been too dearly purchased. But notwithstanding the fanaticism that originated, and the folly that conducted them, the Crusades were not productive of unmitigated evil. The feudal chiefs became better members of society, by coming in contact, in Asia, with a civilization superior to their own; the people secured some small instalments of their rights; kings, no longer at war with their nobility, had time to pass some good laws; the human mind learned some little wisdom from hard experience, and, casting off the slough of superstition in which the Roman clergy had so long enveloped it, became prepared to receive the seeds of the approaching Reformation. Thus did the all-wise Disposer of events bring good out of evil, and advance the civilization and ultimate happiness of the nations of the West, by means of the very fanaticism that had led them against the East. But the whole subject is one of absorbing interest; and if carried fully out in all its bearings, would consume more space than the plan of this work will allow. The philosophic student will draw his own conclusions; and he can have no better field for the exercise of his powers than this European madness; its advantages and disadvantages; its causes and results.
FWIW, in the introduction, Mackay does describe the outrages that the Turkish rulers of Jerusalem perpetrated upon the Christian pilgrims.
From the Madden article, I discovered Runciman, and went on to read his very good book about the Byzantine Empire.