By 481 [[BC]], A large Persian force (described as 5 million by [[Herodotus]], though this is wildly improbable) had been assembled to march along the northern coast of the Aegean into Greece. This was disturbing to the Greek city states, who convened at the [[Isthmus of Corinth]] to discuss the threat caused by the Persians. | By 481 [[BC]], A large Persian force (described as 5 million by [[Herodotus]], though this is wildly improbable) had been assembled to march along the northern coast of the Aegean into Greece. This was disturbing to the Greek city states, who convened at the [[Isthmus of Corinth]] to discuss the threat caused by the Persians. |