Title: The 300 Spartans
Year: 1962
Director: Rudolph Maté


The basic story is that of the Battle of Thermopylae.

IMDB givest the following trivia:

While most of the Spartans wear the correct headgear, Leonidas and his officers wear Roman legionnaire style helmets that wouldn't be around for about 200 years. (This may have been so that they could easily be identified.)

Spartan physician states that spear has missed an artery. Many centuries early for circulatory system knowledge
 

All about the movie provided by IMDB.