Ready for a quick history lesson? Here we go.

From 1095-1291, Christians and Muslims fought a series of wars over who got to control the holy lands in the Middle East, in particular the city of Jerusalem. (Some crusades were also launched against non-Christians and heretics in Europe, for example in the Baltic countries and southern France.) The conflicts lasted for close to two hundred years, and together, these wars were called the Crusades. Individually, they were called the First Crusade, the Second Crusade, the Third Crusade, and so on. (Source)

The title Indiana Jones and the Last Crusade is a nod to these legendary skirmishes. Indiana and Donovan aren't battling for holy territory—though they are following the trajectory of the Crusaders from Western Europe into the Holy Land—but they are fighting over one of the most important religious artifacts ever, the Holy Grail. Secure that sacred cup, and you could probably control whatever land you want: Jerusalem, Wyoming, Tomorrowland, you name it.

So why is this the last crusade? Well, for one thing, it's the most recent. This crusade is happening in 1938, way after the last major official crusade ended in the 13th century. But more than that, this film, at the time, was the last stop for Indiana Jones. The final installation in the Indy trilogy, Last Crusade aims to show our hero going on his most important adventure: finding his father and reestablishing a relationship with him.

What this flick shows, even in its title, is that family, love, and relationships are more important than any artifact could ever be. They're even more important than immortality and world domination.

That's some deep stuff.