Why were ancient greek communities isolated from each other?

answer; i believe the two groups were irish immigrants and chinese immigrants;

answer: both considered peasants valued members of society.

explanation: the ancient chinese and indian empires were large asian empires that had the same problems with other big empires, they had to work hard and sometimes fight in order to keep them united, they both relied heavily on their capacity to trade and to send strange and rare items to europe, and had the father as the head of the house hold in both societies, but they didn´t considered pleasants as valued members of their society, they were the bottom of the social pyramid in both of their societies.