I must admit, I did not understand how finding Mary Magdalene's sepulchral (the central focus of the movie) would effect anything. In the film, certain individuals wanted to find her coffin so that they could have access to her bones and conduct DNA testing on them and on Audrey Tautou so that they could prove that Audrey was Mary Magdalene's descendent and also, therefore, a descendent of Christ. This makes no sense to me for several reasons.

1. There would be no way of proving that the bones in the sepulchral really were those of Mary Madgalene.
   
2. Even if you could prove they were, there would be no way of empirically proving she had been married to Christ.
   
3. Even if you could prove empirically that she was married to Christ, there would be no way of proving that any of her offspring were, in fact, also His offspring.
   
4. Even if you could prove that Mary Magdalene had been married to Christ and had given birth to His child, that would not necessarily disprove His divinity.
   
5. Even if you could prove that Mary Magdalene had been married to Christ, that her child was His child, and that He was, in fact, not divine, very few people would care. Christianity has existed for 2,000 years and is a wide-spread and well-established religion. I doubt most people would give it up if only because Christianity is a large part of their culture and they find it comfortable and it is human nature to value the familiar and the comfortable even at the expense of what is true.