When was ancient Greece founded and by who?

Ancient Greece wasn't "founded", it just kind of happened and no particular person sat down and wrote up the "Constitution of Ancient Greece."

Rather, it was a collection of independent city-states founded at various times by different people or groups of people, who certainly would not have regarded themselves as "ancient" anything, but rather as the very cutting edge and pinnacle of culture (and in some ways they were right to do so).