As for Xerxes' capacity for tolerance and the Platonic concept of international law, it seems to have been null and void. The tyrant was so confounded by the manly conduct of Leonidas that Xerxes searched out his body from the piled dead, severed the head from the lifeless corpse, and caused the trunk to be nailed to a wooden cross.
And the rest, as we say, is history. There are many stories of men who for one reason or another survived the Battle of Thermopylae; their lives and the manner of their deaths await the curious reader.
In time Leonidas' countrymen would erect a stone lion to his memory at the place of the Hot Gates, and there too the Greeks placed a votive stone which reads:
Go, stranger, to Lacedaemon and tell
That here, obeying her behest, we fell.
