Hercules is the Roman name given to this mythological character. However, the rest of the god's and goddess's names in the movie are from the Greek interpretation of the myths (Zeus, Hermes, Ares). Hercules's name in Greek is actually Heracles, but is known more commonly by it's Roman name. If the movie was meant to tell the story to kids, Disney should have written the correct name as not to confuse them later between the Greek and Roman names.