It is said that Leonidas himself sent them away because he was concerned that they would be killed, but felt it not fitting for himself and the Spartans to desert that post which they had come to defend at the beginning.

I, however, tend to believe that when Leonidas perceived that the allies were dispirited and unwilling to run all risks with him, he told then to depart. For himself, however, it was not good to leave; if he remained, he would leave a name of great fame, and the prosperity of Sparta [22.4417,37.0667] (Perseus) Sparta would not be blotted out.

When the Spartans asked the oracle about this war when it broke out, the Pythia had foretold that either Sparta [22.416,37.83] (inhabited place), Laconia, Peloponnese, Greece, Europe Lacedaemon would be destroyed by the barbarians or their king would be killed. She gave them this answer in hexameter verses running as follows:

For you, inhabitants of wide-wayed Sparta [22.4417,37.0667] (Perseus) Sparta,Either your great and glorious city must be wasted by Persian men,Or if not that, then the bound of Sparta [22.416,37.83] (inhabited place), Laconia, Peloponnese, Greece, Europe Lacedaemon must mourn a dead king, from Heracles' line.The might of bulls or lions will not restrain him with opposing strength; for he has the might of Zeus.I declare that he will not be restrained until he utterly tears apart one of these.Considering this and wishing to win distinction for the Spartans alone, he sent away the allies rather than have them leave in disorder because of a difference of opinion.