The Persian strategy for 480 BC was probably to simply progress through Greece in overwhelming force.[181] The cities in any territory that the army passed through would be forced to submit or risk destruction; and indeed this happened with the Thessalian, Locrian and Phocian cities who initially resisted the Persians but then were forced to submit as the Persians advanced.[195][196] Conversely, the Allied strategy was probably to try and stop the Persian advance as far north as possible, and thus prevent the submission of as many potential Allies as possible.[183] Beyond this, the Allies seem to have realised that given the Persians' overwhelming numbers, they had little chance in open battle, and thus they opted to try to defend geographical bottle-necks, where the Persian numbers would count for less.[183] The whole Allied campaign for 480 BC can be seen in this context. Initially they attempted to defend the Tempe pass to prevent the loss of Thessaly.[183] After they realised that they could not defend this position, they chose the next-most northerly position, the Thermopylae/Artemisium axis.[183] The Allied performance at Thermopylae was initially effective; however, the failure to properly guard the path that outflanked Thermopylae undermined their strategy, and led to defeat.[183] At Artemisium the fleet also scored some successes, but withdrew due to the losses they had sustained, and since the defeat of Thermopylae made the position irrelevant.[197] Thus far, the Persian strategy had succeeded, while the Allied strategy, though not a disaster, had failed.