Another misconception also is the Spartan force of 300 elite hoplite soldiers fought on their own against the 100,000-150,000 or so Persian troops. This is of course false as they had a Greek force of about 4,000 with them the first two days and a force of approximately 700 Thespians and 400 Thebans who had chosen to stay on the final day, despite Leonidas' orders for the Greek forces to retreat to evade certain death. This misconception again, is to glorify the Spartans and their efforts at Thermopylae. Their three day standoff still being an amazing feat of military prowess and elite soldier mentality, one cannot deny them this. Over all, there were 300 Spartan casualties (including Leonidas, the Spartan king), and most of the Thebans and Thespians that didn't surrender as the Persians lost close to over 20,000 men, including the death of all 10,000 of their Immortals (deemed 'Immortals' due to the swift replacement of an injured/killed Immortal, keeping their unit of 10,000 at a constant number so it would seem their force and cohesion was never changing, constantly powerful and constantly geared for war; hence immortal).
A certain individual that must be looked at seriously from the battle of Thermopylae is