The novel explores an alternative religious history, whose central plot point is that the Merovingian kings of France were descended from the bloodline of Jesus Christ and Mary Magdalene, ideas derived from Clive Prince's The Templar Revelation (1997) and books by Margaret Starbird. The book also refers to The Holy Blood and the Holy Grail (1982) though Dan Brown has stated that it was not used as research material.
The Da Vinci Code provoked a popular interest in speculation concerning the Holy Grail legend and Mary Magdalene's role in the history of Christianity. The book has, however, been extensively denounced by many Christian denominations as an attack on the Roman Catholic Church, and consistently criticized for its historical and scientific inaccuracies.