Director Zack Snyder has revealed he and 300 collaborator Kurt Johnstad have begun writing the script for the sequel Xerxes.

The first artwork from Frank Miller's long-discussed six-issue prequel was released just last month, at which time Snyder and producer Thomas Tull said they'd likely pursue the adaptation. "If the book is awesome and compelling," Snyder said at the time, "then, yes, we're interested."

Apparently Miller's comic met those criteria, as Snyder now tells Hero Complex, "We closed the writing deal on Xerxes. We started writing about a week ago. So we're doing it. It's happening."

But while Snyder has a first-look deal with Warner Bros., which will release his Sucker Punch next year, there's no agreement in place yet for Xerxes.

As Miller first revealed in December, Xerxes will take place 10 years before Thermopylae, beginning with the legendary Battle of Marathon, which marked the end of Persia's first invasion of Greece.

"The story will be the same heft as 300 but it cover a much, much greater span of time -- it's 10 years, not three days," he told the Los Angeles Times last month. "This is a more complex story. The story is so much larger. The Spartans in 300 were being enclosed by the page as the world got smaller. This story has truly vast subjects. The Athenian naval fleet, for instance, is a massive artistic undertaking and it dwarfed by the Persian fleet, which is also shown in this story. The story has elements of espionage, too, and it's a sweeping tale with gods and warriors." He said that while Xerxes is the title character, the protagonist is Themistocles, the famed Athenian politician and general.