Korea has lost (to a bear) their starting warrior and therefore is very likely not to be able to see the copper that Rome will settle soon.
To make it worst, Rome might notice the decrease of power (edit - or not they discover BW at the same time, could be a blessing to bring confusion about the discovered tech)
To make it worst, Rome might notice the decrease of power (edit - or not they discover BW at the same time, could be a blessing to bring confusion about the discovered tech)