Even people who couldn’t tell George Santayana from Carlos Santana are familiar with some form of his dictum that those who cannot remember the past are condemned to repeat it. Like most famous comments, it’s been overplayed, and many people tend to quote it glibly, without thinking about it; but it’s still an important warning of the consequences of failing to understand our history. To this, we might add that those who don’t remember the past will have no sense of perspective about the present.

I was reminded of that truth recently in reading the novelist Sandra Dallas’ review of the book Verne Sankey: America’s First Public Enemy, by South Dakota circuit judge Timothy Bjorkman. As the title indicates, Sankey was the first person ever to be named Public Enemy #1 by the FBI, “because he was the first to realize that in the wake of the Lindbergh baby abduction, kidnapping could be a lucrative gig”; he’s little remembered today because he wasn’t flashy, while so many of his criminal contemporaries were. As Ms. Dallas writes, “This was the Great Depression, when the rich were held in low esteem and the robbers and others who preyed on them were rock stars, glorified by the press. It was the era of Bonnie and Clyde, Pretty Boy Floyd, John Dillinger and Machine-Gun Kelly.” That set me thinking, because there’s much complaint in certain quarters about the glorification of street thugs by segments of American culture—which I certainly agree is a bad thing; but it’s often joined to the assumption that America is in decline from some past golden age when these things didn’t happen, and that just isn’t true. One might, I suppose, argue that the thugs some people glorify these days lack the style of past generations of celebrity criminals; but if we’re honest, we have to admit they’re really very little different.

The reason Santayana’s comment is largely correct is that if we don’t understand our past, we really can’t understand our present, either—which leaves us vulnerable to those who would use a skewed picture of the past against us. Granted, a truly unbiased understanding of history is probably beyond our grasp, but we need to get as close as we can in order to defend ourselves against those who interpret it to serve their own agendas (whatever those might be).

Perhaps the most significant example of this nowadays is in regard to Islam, where the Crusades are often presented as a great crime by Christendom against an unoffending Moslem world, launched for no apparent reason. The truth of the matter is far different. As Hugh Kennedy shows in his book The Great Arab Conquests: How the Spread of Islam Changed the World We Live In, the early 7th century AD saw a new propulsive force break into world history: the conquering armies of Islam. Within the first hundred years, they had spread across most of the Christian world, and as Dr. Philip Jenkins notes in his excellent review in Christianity Today, “Before the Crusades”, this “tore Christianity from its roots, cultural, geographical, and linguistic.” The Islamic conquests essentially created the Western Christianity we now know, as the church was forcibly disconnected from its Asian heritage and character; and the Muslim armies didn’t stop there, occupying most of Spain, invading Italy and the Balkans, and even reaching as far as the gates of Vienna.

However wrong the Crusades went over time (such as the Fourth Crusade, which conquered and sacked not Muslim Jerusalem but Orthodox Constantinople, in whose defense the First Crusade had been launched), they began as a defensive action, a grand counter-attack intended to roll back the Muslim armies before they conquered all of Europe. In the end, they didn’t succeed; it would not be until the breaking of Ottoman power at the Battle of Vienna in 1683 that the tide of Islamic conquest would finally turn for good. Still, though we must never gloss over all the wrongs committed by Crusaders, it’s important to understand that the Crusades as such were an eminently justifiable military and cultural response to Islamic military aggression; they were a counter-attack launched in a great war begun by the other side.