300: Rise of an Empire (2014), directed by Noam Murro, expands the stylized war saga to naval conflicts between Greece and Persia. Running parallel to the events of 300, the film centers on Athenian general Themistocles and the ruthless Persian commander Artemisia. The emphasis shifts toward sea battles and spectacle-driven action.

Från IMDB:
Greek general Themistocles of Athens leads the naval charge against invading Persian forces led by mortal-turned-god Xerxes and Artemisia, vengeful commander of the Persian navy.