One of the myths of modern liberalism is that the Crusades were assaults upon “Moslem countries” by Christians.  Never mind the fact that Syria, Palestine, Egypt, Armenia, and Asia Minor (now Turkey) were Christian countries for centuries before the Moslems conquered them.  At worst, the Crusaders were recovering lands that had been theirs.  Belloc has several good things to say about the loss of these once Catholic countries.  We are right to mourn their conquest by the Turk and Saracen.  However, we should also keep in mind the fact that at the time of the Mohammedan conquest most of these countries had already fallen into heresy or schism.  The Christians of what are now Iraq and Iran had turned Nestorian.  Egypt, Syria, and Armenia had gone Monophysite.  The Orthodox Christians of the Byzantine Rite for the most part defected when Michael Caerularius went into schism in 1054.  Only the Maronites of Lebanon maintained their union with Rome, and many scholars contest even their claim to continuous Catholicism (the opposing view is that they became Monothelites); I am inclined to give them the benefit of the doubt.  So by the time of the First Crusade there may have been almost no Catholics anywhere in the Middle East. 

Now, since the Mohammedan conquest and the Crusades representatives of *every single* dissident group in the Middle East have re-established communion with Rome.  There are now Catholic communities among the  former Monophysites (the Coptic, Armenian, and Syrian Catholics), the former Byzantine schismatics (the Melkites), and the former Nestorians (Chaldeans), plus the Maronites, who are all Catholic.  I think it reasonable to suppose that Islamic ascendancy helped prompt these groups to humble soul-searching and ultimately to a greater openness to Rome.  As a result, there may be more Catholics in the Middle East today, and of all the Rites of the Church, than there were at the time of the Crusades.  Thank God for this silver lining to the Mohammedan conquest!