What Inspired Frank Miller To Write The Comic Called The '300'?

Frank Miller has himself claimed that he was inspired by the 1962 film called "The 300 Spartans" which he saw as a child. Even the Producer of the film, a Gianni Nunnari had a fetish for the Battle of Thermopylae. Like the film made by Frank Miller this earlier work was also not free of controversy; with overtones of the cold war making their way into the film. Sparta was depicted in both films as a bastion of freedom which it was not.

Any how Mr. Miller claimed that watching the film did wonders for him. In his words "it changed the course of my creative life". Both works depict the Battle of Thermopylae where a vastly outnumbered Greek army led by the Spartans made a last stand against a mammoth Persian invasion force assembled by Emperor Xerxes.