Now, you do not have to be a Muslim to think that for the bishop of Rome to cite this is the most perfect hypocrisy. There would have been no established Byzantine or Roman Christianity if the faith had not been spread and maintained and enforced by every kind of violence and cruelty and coercion. To take Islam’s own favorite self-pitying example: It was the Catholic crusaders who sacked and burned Christian Byzantium on their way to Palestine—and that was only after they had methodically set about the Jews, so the Muslim world was actually only the third victim of this barbarity. (Sir Steven Runciman’s A History of the Crusades is the best source here.) ~Christopher Hitchens, Slate

Well, in fact, established Christianity and violently coercive Christianity are not the same thing, as I have been reiterating again and again and again.  There have been periods in Christian history where there has been violent coercion by the state against heretics.  But Christians’ first recourse has historically typically not been to violent persecution or to warfare.  Certainly if we are comparing the records of the Byzantines in particular with the record of Islam, the contrast becomes even more remarkable.  So we can dismiss Hitchens on that point.  Next we might note that Hitchens cannot even get his facts straight–the purported ultimate target of the Fourth Crusade was supposed to be Egypt, not Palestine, just as the ill-fated Fifth Crusade would be as a way of knocking out the Ayyubid support structure that kept the Crusader States pinned to their narrow strips of Levantine territory. 

And as much as I respect the late Sir Steven Runciman and enjoy his works enormously (and I have heard tell that he converted to Orthodoxy at the end of his life), Hitchens might try something more modern than Crusades histories that are half a century old and out of date.  Sir Steven was a great friend to Byzantium and a great protector of her reputation; he did a good deal to revive interest in and respect for Byzantium as a worthy subject of study and as an admirable civilisation, for which all Byzantinists should be grateful, but his own love for Byzantium tended to make him an extremely harsh and sometimes unbalanced critic of the western Europeans who were the main actors of the drama.  He famously referred to the sack of Constantinople in 1204 as the greatest “crime against humanity” ever, which is flattering to the Constantinopolitans but hardly accurate.  Michael Angold has written a book on the Fourth Crusade offering a radical corrective view of this assuredly exaggerated judgement of the Crusade.  For the best general Crusades historians, look to Riley-Smith or Madden, who have done great work attempting to understand the phenomenon of the Crusades rather than sit in judgement over it.