The studio acquired a pitch in October 2011 from Iowa author and two-time Jeopardy! champion James Erwin back in October 2011. The pitch was based on his Reddit thread, which sought an answer to the following question, "What if a unit of U.S. Marines are transported back in time and forced to do battle with Roman legions?" James Erwin wrote a draft of the screenplay, but the studio wanted a fresh take, which is where Brian Miller comes in. The story has already been tweaked slightly, with the plot centering on a U.S. Special Forces team, instead of Marines.