Meeting Vetra's daughter, Vittoria, Langdon learns that the Illuminati, an ancient anti-religious sect, plan to destroy Vatican City with an antimatter canister invented by Vetra refashioned as a weapon. When physicist Leonardo Vetra is murdered and branded with the word Illuminati, his boss, CERN director Maximilian Kohler, asks Harvard symbologist Robert Langdon for help. Brown states on his website that his books are not anti-Christian, and that he is on a 'constant spiritual journey' himself. Brown's novels that feature the lead character also include historical themes and Christianity as motifs, and as a result have generated controversy. Langdon is portrayed as a Harvard University professor of religious iconology and symbology, a fictional field related to the study of historic symbols, which is not methodologically connected to the actual discipline of semiotics. The Robert Langdon book series is named after Robert Langdon, the protagonist of the novels by American author Dan Brown. Box set of the first four books in the series with their British covers For the franchise, see Robert Langdon (franchise). For the titular character, see Robert Langdon.
