Ancient Greece
Later, during the Classical period, the leagues were fewer and larger, and dominated by one city (particularly Athens, Sparta and Thebes). Often cities would be forced to join under threat of war or as part of a peace treaty. After Philip II had conquered the heartlands of ancient Greece, he did not try to annex the territory or unify it into a new province. However, he forced most of the cities to join his own Corinthian League.