Author Henry Lincoln explains the original background to the 'Holy Bloodline' hypothesis, later featured in Dan Brown's bestselling novel "The Da Vinci Code".Author Henry Lincoln explains the original background to the 'Holy Bloodline' hypothesis, later featured in Dan Brown's bestselling novel "The Da Vinci Code".Author Henry Lincoln explains the original background to the 'Holy Bloodline' hypothesis, later featured in Dan Brown's bestselling novel "The Da Vinci Code".