Vandelay said:I´d recommend against hardcoded rivalries like Rome vs. Carthage. Such rivalries should come from the geo-political sitiuation - bordering nations, trade conflicts, sponosring of piracy etc..
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Unluckily, EUR rules doesnt allow for trade conflicts or piracy, so geopolitical reasons for rivalry are quite limited. But I see your point.
Another option would be making military party 'hate' those countries that control any of your nations' core provinces. Or merchantile party 'hate' those countries that have some resource that you're in badly need of but refuses to trade it with you...