Gibson got the theology right in "The Passion," so why couldn't he have gotten the historical details right too? Why did he insist that Jesus carry his entire cross to Calvary, when anyone who has read a bit of ancient history knows that condemned Roman prisoners carried only the crossbeam lashed to their shoulders, as the two thieves do in Gibson's film? The soldiers fix the nails into Jesus' hands in the middle of the palm (which would have torn away from the cross), not through the wrist bone as was more likely. And some characters in the film wear caricatures, not faithful reproductions, of ancient costumes -- such as the Temple guards, who dress like Orcs out of "The Lord of the Rings," or the epicene, naked-to-the-waist Herod Antipas (Antipas was irreligious but also a canny and sensible politician).
It was fine for Gibson to have the Roman soldiers speaking Latin, for Roman legionaries had to be Roman citizens, which in Jesus' time usually meant being born near Rome. But the soldiers, along with Pilate and his wife, don't use the hard-consonant classical Latin pronunciation that prevailed during the 1st century. Rather, they use a softer medieval "church" Latin pronunciation that makes them sound like modern Italians. In fact, I swear that I heard a soldier in the movie shout, "Faccia!" ("Do it!") in Italian, when the correct Latin would have been "fac" or "facias." And if Gibson went to the trouble of commissioning a Latin-Aramaic screenplay, why didn't he go all the way and capture the truly polyglot nature of ancient Judea, in which everyone's second language was Greek, and Jerusalem at Passover would have been filled with Greek-speaking Jewish pilgrims from abroad?
These are all niggling mistakes, to be sure, but they come up constantly in "The Passion." Furthermore, there are academics who combine sophisticated New Testament scholarship and genuine Christian faith and could have helped Gibson make a more persuasive film. To name a few: Luke Timothy Johnson, a Catholic; N.T. Wright, an Anglican; Ben Witherington, an evangelical Protestant. But their voices have been drowned out, leaving Gibson to follow his own misapprehensions about Jesus' world, by the John Dominic Crossans who have managed to persuade us that faith and scholarship don't go together.