"We closed the writing deal on ‘Xerxes.’ We started writing about a week ago," Snyder said. "So we’re doing it. It’s happening… I don’t have a directing deal in place but we are writing it, so call it intent."
The movie is neither a prequel or sequel to 300.
"This movie follows Themistocles and the Battle of Artemisium, which coincidentally happens on the exact same three days as the Battle of Thermopylae [which was the basis of '300']," Snyder added. "This one starts off with a quick retelling of the why of the Persian wars. It starts off at the Battle of Marathon and then it goes back to Themistocles finding out that Persians are invading again. and off we go over to learn a little bit about why Xerxes is the way he is."
You can read more on what to expect here!