Da Vinci knew a lot about the real history of "Christ" that few knew about and used this knowledge in his paintings. Da Vinci was familiar with the French libraries (he died in France) as well as the Windsor Library which contains not only some of Da Vinci's manuscripts but also information related to the "true authorship of the New Testament" (Josephus), information also known to Shakespeare and later Joseph McCabe. The Da Vinci's "code" was not much of a code. He wrote some of his manuscripts backwards so you had to use a mirror to read it. This was presumably to keep prying eyes away from his material. Since he was ambidextrous, he simply wrote backward with his left hand. The material in "The Da Vinci Code" is mostly baloney. I don't think that Da Vinci knew the alleged location of Mary Magdelen's sarcophagus (the Roslyn Chapel in Scotland) supposedly placed there by the Knights Templars.