In August 2005 author Lewis Perdue unsuccessfully sued Brown for plagiarism, on the basis of claimed similarity between The Da Vinci Code and his novels, The Da Vinci Legacy (1983) and Daughter of God (2000).
In April 2006 Brown's publisher, Random House, won a copyright infringement case brought by authors Michael Baigent and Richard Leigh, who claimed that Brown stole ideas from their 1982 book Holy Blood Holy Grail for his 2003 novel The Da Vinci Code.