Passage: In June 2013, Warner Bros. announced that director Zack Snyder and screenwriter David S. Goyer would return for a Man of Steel sequel, with the studio considering the release for the film in 2015. The following month, Snyder confirmed at San Diego Comic-Con International that the sequel to Man of Steel would feature Superman and Batman meeting for the first time on film. Goyer and Snyder would co-write the story, with Goyer authoring the script despite saying in 2006 that a 'Batman Vs. Superman' film "is where you go when you admit to yourself that you've exhausted all possibilities ... an admission that this franchise is on its last gasp", and Christopher Nolan involved in an advisory role as executive producer. According to Snyder, the film would take inspiration from the comic The Dark Knight Returns.In November 2013, Snyder clarified his film would not be based upon the aforementioned graphic novel. "If you were going to do that, you would need a different Superman. We're bringing Batman into the universe that now this Superman lives in." Batman v Superman marks the first appearance of Wonder Woman in a live-action, theatrical film, which Warner Bros. had been developing as far back as 1996. In December 2013, Chris Terrio was hired to rewrite the script, due to Goyer's commitments to other projects. Further commenting on the influences, Terrio revealed in an article published by The Wall Street Journal that the movie would draw inspiration from Nolan's Batman trilogy, Italian semiotician Umberto Eco's 1972 essay "The Myth of Superman", and the W.H. Auden poem "Musée des Beaux Arts" which contrasts the quotidian details of normal people's lives with the epic struggles of mythological figures. According to him, "In superhero stories, Batman is Pluto, god of the underworld, and Superman is Apollo, god of the sky. That began to be really interesting to me — that their conflict is not just due to manipulation, but their very existence." The Joker and the Riddler were supposed to appear in the film, but Snyder...

Question: What year did Chris Terrio start rewriting Batman V. Superman?
2013