"Da Vinci Code" DVDs do their homework

What contribution did the Knights Templar — the European "warrior monk" order that guarded the Holy Grail during the Middle Ages, according to "The Da Vinci Code" — make to international banking? (Answer: The Templars invented it.)

What was overachieving brainiac Leonardo da Vinci's unfulfilled ambition until late in life, when bloodthirsty Cesare Borgia became his patron? (Answer: weapons design. No kidding.)

I don't mean to brag, but I know stuff thanks to Dan Brown's best-selling "The Da Vinci Code," the basis for the Ron Howard-Tom Hanks movie opening today. I don't mean stuff I picked up just from Brown's book, but from related DVDs released since "The Da Vinci Code" was published in 2003.

Little did I know three years ago, while reading Brown's suspenseful story about a plot to suppress evidence of the real relationship between Jesus Christ and Mary Magdalene, that a small industry in DVDs piggybacking "Code's" success was about to thrive.

Nearly all of them use Brown's wildly successful novel as a jumping-off point for investigating allegations that da Vinci, the Italian Renaissance engineer and artist, belonged to the Priory of Sion. Supposedly, da Vinci kept the whereabouts of the Grail secret, encoding his paintings (such as "The Last Supper") with information about the legendary artifact.

The deeper and more sensitive suggestion that Christ's bloodline exists today is what prompts more passionate debate, as well as probes that range from lazy to dogged.

The DVDs below are among the best and most intriguing on the subject, some supporting, some refuting "The Da Vinci Code":

• "Da Vinci Code Decoded" (2004): This one is guaranteed to send a chill up the spine. Richard Metzger's documentary gathers several authors and historians whose work Brown researched (including Henry Lincoln, who co-wrote the landmark 1982 "Holy Blood, Holy Grail" and unsuccessfully sued Brown for plagiarism). These folks provide an overview of the allegedly heretical subtext of da Vinci's few paintings. Several of their observations (including a rather earthy one about an image of Christ's mother) are even more startling than their reflections on that famous "V" between Jesus and the figure who might be Mary Magdalene in "The Last Supper." (If you don't understand, you will when you see Howard's film.) Then there's the weirdly disembodied, knife-wielding hand in that same painting ... Yeesh.

• "ABC News Presents: Jesus, Mary and Da Vinci" (2004): This television special has Elizabeth Vargas hopscotching through France, Scotland, Italy and the Holy Land seeking, among other things, impossibly elusive evidence of Christ's descendants. She strikes out a lot but does better looking into the da Vinci connection. There's a great moment when she stands before "The Last Supper" with Umberto Eco, author of "The Name of the Rose," while he insists the very feminine St. John figure (thought by some to be Mary Magdalene) can't possibly be a woman. Vargas also reveals much about the Roman Catholic Church's systematic destruction of Mary Magdalene's reputation over the ages, lowering her status from apostle-equivalent to prostitute.

• "Where Facts and Fiction Meet: The Biblical Christ in a Da Vinci Code Society" (2005): Needless to day, some Christians have taken umbrage at revisionist speculation about the marital status of Jesus. This video is one of several that counters Brown's premise on biblical-historical grounds. Divided into six subtopics, this smoothly produced film is beautifully illustrated and compelling.

• "Exploring the Da Vinci Code" (2000): This video, made before publication of Brown's book, puts us back into the hands of Lincoln who, along with Michael Baigent and Richard Leigh, first alleged a union between Jesus and Mary Magdalene and the existence of the Priory of Sion. This slow-going program finds Lincoln, who has lived near Rennes-le-Château, leading viewers on a tour of that village's church, which, some maintain, provides clues about Christ's progeny and the location of the Grail. It's interesting to meet Lincoln before he got so litigious regarding Brown, but especially before one takes a look at the following video.

• "The Real Da Vinci Code" (2005): This is the best and easily most entertaining of the batch. Hosted by Tony Robinson (that's right, "Blackadder's" Baldrick), this Channel Four Television special from Britain irreverently but methodically picks apart so-called historical facts Brown put forward. Like Vargas, Robinson zips around the world (though I'd rather hang with him) looking for proof that the major players (the Knights Templar, the heretical Cathars) in Brown's version of the Grail legend actually did the things he and his sources said they did. Whaddya know: Most of what Brown and Lincoln and the rest of the crowd tell us we should take for granted is full of holes, not least of all the Priory of Sion, which, according to this program's damning evidence, was a huge hoax. Between bursts of wit (a comic-book presentation of Christ and Mary Magdalene's romance), glimmers of hope for conspiracy buffs emerge, such as the irrefutable Magdalene cult reflected in the pages of the Gnostic gospels.

Tom Keogh: tomwkeogh@yahoo.com