I was playing as orange and allied with yellow and green
all of a sudden green took my capital and several countries without declaring war on me
i could not do anything as my cities became 'allied cities' that i cannot attacked
i waited 2 turns and loss the game cos this person controlled my capital for 2 turns
i am really new to this game. Is there something about breaking alliance without declaring that i dont know
or is this guy actually using some sort of cheats