"There's an extended scene set in Persepolis," adds Miller, "for instance, where he [Xerxes] takes power and there are several scenes where he is going through his transitions and he's shown speaking to his mother and his wife..."The wife is unnamed, but among the various contenders for who this might be is the biblical queen, Esther. It's true that we're unclear whether the king she married was Xerxes I, Artaxerxes I or even Artaxerxes II, and even if it was Xerxes I then it could be either his wife Amestris or even Vashti that Miller is thinking of. Nevertheless there is a chance it could be Esther.
That said, Xerxes and Vashti are also biblical characters to an extent so even their portrayal would be of some relevance. It's quite interesting to juxtapose portrayals of Xerxes in Esther films with that in 300: in the former Xerxes is usually portrayed (bizarrely in my opinion) as a hero, whereas in 300, and the Greek historical sources that the film is very loosely based on, he is very much the villain.
has also covered the story.