Published in 2000, it introduces the character Robert Langdon, who is also the principal character of Brown’s subsequent novel, The Da Vinci Code. It also shares many stylistic elements with the latter, such as conspiracies of secret societies, a single-day time frame, and the Roman Catholic Church. Ancient history, architecture, and symbolism are heavily referenced throughout the novel. A film adaptation of the same name is due for release on May 15, 2009.