Heligt Blod Helig Gral - Michael Baigent, Richard Leigh & Henry Lincoln is a non‑fiction investigative book that explores a controversial theory about the history of Christianity, the Holy Grail and possible hidden lineage of Jesus. The authors trace supposed secret parchments found in southern France, secret societies like the Priory of Sion, the Knights Templar and the Merovingian dynasty, ultimately suggesting that Jesus may have married, had children and that his bloodline continued in Europe. A claim that sparked worldwide debate and inspired later fiction such as The Da Vinci Code.