Director Zack Snyder has talked about his plans for the upcoming 300 spinoff, Xerxes while in London last week doing press for Legend of the Guardians. Described as a “spinoff” as Snyder says that Xerxes isn’t a “prequel or a sequel” because it’s about the Battle of Artemisium, which took place during the exact same three days as the Battle of Thermopylae .
"We’re doing all these sequences were the triremes all crash together and the battlefield is all the boats crashing together so the men run across the ships as they’re fighting, so that should be fun. And horses and everything. It’s crazy."
Snyder states that he’s writing the film right now, but since he’s just been hired to direct Superman: The Man of Steel, don’t expect to see any big movement on Xerxes anytime soon unless Snyder decides to let someone else direct and stays on only in a producing/screenwriting capacity, with the recent doubts surrounding the project.
It’s worth nothing that Frank Miller, who wrote the 300 graphic novel, is also writing a comic mini-series of Xerxes, but his version sounds very different. Miller’s Xerxes will take place over the span of ten years and also involves gods. The mini-series is due out next year.