I cannot emphasize strongly enough the importance of catechists and church ministers maintaining exceptional competence in understanding and explaining the Crusades, if for no other reason than the tendency of any critic of the Church to throw the Crusades and the Inquisition into the thick of the argument. To deny the Church’s culpability will destroy your reputation for both competence and honesty.
If you have the leisure, I strongly recommend the most highly respected British historian of the Crusades and the downfall of Constantinople, Sir Steven Runciman. His multi-volume treatise was written in the early 1950’s but was reissued by popular demand in the late 1980’s. Volume I covers the First Crusade; Volume II the Second, and the final crusades in Volume III.
If you wish to focus on one Crusade to begin (naturally the first), I recommend Thomas Asbridge, The First Crusade: A New History (2004). This is an engrossing account of the epic military movement that began with Pope Urban’s cry, “God Wills It” in 1095 through the Sack of Jerusalem on July 15, 1099. Of particular value is Asbridge’s opening essay on the multiple causes of the First Crusade (pp. 1-39), without which no understanding is truly possible. (See my review on the Amazon site, January 27, 2007)
It is also important to note that no two crusades were alike, and that the business and efficiency of crusading, so to speak, made great strides over the following century. Thus we come to the Fourth Crusade; a string of events that even today leads historians to shake their heads. I recommend here one of the most compelling historical “reads” of my adult life, Jonathan Phillips’ The Fourth Crusade and the Sack of Constantinople. (2004) Although its destination was the recovery of Jerusalem, this Crusade ended up going north instead of south and ravished the seat of Eastern Orthodox Christianity, Constantinople. Phillips notes that in 2001 Pope John Paul II himself “issued an extraordinary statement—an apology to the Greek Orthodox Church for the terrible slaughter perpetrated by the Warriors of the Fourth Crusade.” I suspect that most Christians/Catholics know virtually nothing of the Fourth Crusade or of the Pope’s apology. But there it is: the Holy Father, himself an eminent scholar, had made the case that there was little to boast of in much of the Crusading history.
The worst strategy would be the eradication of this episode of our history from our collective ecclesiastical memories. The Crusades are a painful lesson that noble ends are never justified by outrageous deeds. Of necessity they must be taught—with all their doleful consequences—as standard catechetical fare. The truth may sicken, but it also sets one free.
(See my review of Phillips' book at its Amazon site, posted August 7, 2005)