How do I improve diplomatic relations with an ally?

[yardsale]

During around the medieval era, some barbarians took several cities of the AI Carthaginian civ that I was sharing borders with. I whipped up an army and took those cities back. Some of them, I razed. Others, I took for myself. And others still, I liberated them back to Carthage. I didn't know that you'd get a diplomatic hit for razing a Barbarian-controlled city that was once an AI civ's city. Since that skirmish, I've had a -5 "You razed one of our cities!" diplomatic relation with Carthage (disregarding all other diplomatic points).

Fast forward to the Future Era. I'm the most powerful civ in the map, and I have extensive trade relations with every civ around the world. I have a positive relation with Carthage - he's Pleased towards me. I want to elevate that to Friendly but I already tried every venue I could to raise diplomatic points with him. We share the same state religion and as many matching civs as my spies would allow. I prioritize him when trading extra resources. I gifted him military units. Yet, that pesky -5 diplo hit from a millenia ago still lingers with no sign of regression.

How do I make him forget/forgive the city razing incident?

 

[georgjorge]

I guess the question of WHY you want to get him to Friendly isn't so important here...

Bonuses you didn't mention:

You can get up to +4 for making him favourable trades (not resources but techs or gold, the more lopsided the better)
You can get +1 for trading him 7 or more techs over the course of the game
You can get up to +3 for sharing a war against another enemy with him (the longer the bigger the bonus)
You can get +2 by voting for him in UN elections if he's eligible (not always possible)

Together with shared religion bonus (+3) and shared civic bonus (+3) as well as bonus for trading him resources for a longer time (+2) that should allow you to get to at least +16. So if the -5 still applies you get to +11 which is enough for Friendly. Once Friendly you can also sign a Defensive Pact for an additional bonus over time.

So: gift him techs or gold, make more resource trades, look for someone to start a war against and bribe him to join.

 

[Lazteuq]

I dont think there is anything you can do about the -5. If you make some really lopsided trades with him, you can have up to +4 "our trade relations have been fair and forthright". Make sure you have open borders, that might get you +2
EDIT: georgjorge just gave a better answer as I was typing this

 

[yardsale]

I admit that it's more for personal satisfaction but moreover, it bothers me quite a bit that the -5 won't go away, especially since like I said it was an accident. Do you guys know if it's permanent or just very slow at dying down? If it's the former then I don't think that that's a fair game mechanic. Relations evolve over time and it doesn't make sense to me that a civ would hold a grudge against the player for the rest of the game for razing one of its cities.

 

[Lazteuq]

Im not sure about that specific modifier, but I know that some modifiers decay over time at random, so the AIs do occasionally forget things. I think they have a chance to forget things like refusing their demands or not joining their wars.

 

[Mizar]

I guess the question of WHY you want to get him to Friendly isn't so important here...

Bonuses you didn't mention:

You can get up to +4 for making him favourable trades (not resources but techs or gold, the more lopsided the better)
You can get +1 for trading him 7 or more techs over the course of the game
You can get up to +3 for sharing a war against another enemy with him (the longer the bigger the bonus)
You can get +2 by voting for him in UN elections if he's eligible (not always possible)

Together with shared religion bonus (+3) and shared civic bonus (+3) as well as bonus for trading him resources for a longer time (+2) that should allow you to get to at least +16. So if the -5 still applies you get to +11 which is enough for Friendly. Once Friendly you can also sign a Defensive Pact for an additional bonus over time.

1. Several of the options you mention have no fixed +x but vary depending on the leader (like religion or shared civic bonus)
2. the threshold when other leader become pleased, friendly,.. also vary.
and there are hidden modifiers you don't see, some also depending on the leader (your's and their's)

 

[Tatran]

For every razed city you will receive 2.5 negative points and it's permanent.
You will get no penalty when the barbarian culture is dominant. I don't know the percentage.

 

[Fippy]

and there are hidden modifiers you don't see, some also depending on the leader (your's and their's)

Small correction, your own leader does not matter for diplo.
Gandhi or Monty, you are never judged before your actions..much unlike those leaders in AI hands

 

[georgjorge]

1. Several of the options you mention have no fixed +x but vary depending on the leader (like religion or shared civic bonus)

Yes, but the ones I gave him are the ones that apply to Hannibal (except the threshold for Friendly, I don't know that exactly).

 

[Tatran]

Hannibal gives +5 for shared religion and +6 if he owns the holy city.
There are a lot of events/quests which will give also positive diplo modifiers. (best defense, famine event, airplane crash, etc)
Liberating cities will give 1.5 points.

 

[rah]

Gift him a crappy city for extra diplo.

 

[shakabrade]

deleted as it was already mentioned, btw this is a good kind of a question