Leonidas was a king of Sparta and because of that he followed the tradition of Sparta. To understand what Sparta was like,, see that Sparta had no walls. The city was not protected. Walls were not needed, because nobody woud dare to attack Sparta.
There was always lots of conflict between the greek city states but when Persia attacked, the city states worked together. Leonidas and his troops pretty much functioned like a roadblock against Xerxes. The persians were very bad strategists and got basicly blocked inside the chasm. There are many famous quotes for Leonidas. When Xerxes meet him, he offered leonidas peace if he lays down his weapons but Leonidas only aswered: Come and get them.
In the end Leonidas and his troops gave the other greek cities enough time to prepare evacuations and counterstrikes. Themistocles of Athens prepared a massive fleet which later on destroyed the entire persian fleet at Salamis. When Xerxes land forces arrived in Athens, the city was empty and evacuated. All women, childen evacuated to other cities.
The battle at Plataea sealed the persians fate.
So if you ever visit Sparta, pay Leonidas I a visit. ^^
