a Roland for an Oliver

An exchange, especially in battle, in which that which is given is equal in measure and might to that which is received. Named for the two legendary medieval knights Roland and Oliver, who fought for the emperor Charlemagne. Their feats and powers were so equally matched that they were considered to be equal measures of military prowess. The rebels might have scored a victory against us earlier, but we'll be sure to give them a Roland for an Oliver in our next offensive.