After several days of fighting, Xerxes grows angry as his army is repeatedly routed by the Greeks, with the Spartans in the forefront. Leonidas receives word sent by his wife that, by decision of the Ephors, the remainder of the Spartan army, rather than joining him as he had expected, will only fortify the isthmus in the Peloponnese and will advance no further. The Greeks constantly beat back the Persians, and following the defeat of most of his personal bodyguard in battle against the Spartans plus the killing/death of Xerxes' own two brothers, Xerxes begins to consider withdrawing to Sardis until he can equip a larger force at a later date. He prepares to withdraw, as advised by Artemesia (who, having a Greek mother, has her own agenda to dissuade the king from continuing the invasion). Xerxes, however, receives word from the treacherous and avaricious Ephialtes of a secret old goat-track through the mountains that will enable his forces to attack the Greeks from the rear. Promising to richly reward the traitorous goatherd for his betrayal (just as Ephialtes had expected) an emboldened Xerxes sends his army onward.