Kingdom split after lost war?

[Taylor]

This luckily didn't happen to me, but to an AI France and I'm trying to figure out what happened.

Here's the situation: Navarra was pretty strong in the Iberian peninsula, but France also held some land in central Spain. Then France attacked Navarra for its claim on Seville, and Navarra called me (England) into the war. Together we had little trouble in defeating the French, and so they lost.

Less than a month later, I get the message that "King Gargamel II of France has usurped the title Kingdom of France from King Gargamel I of Andalusia." Apparently Gargamel I held two king titles, of which France was usurped away from him, and now he has only Andalusia left. But how did that happen? France just looked normal to me (not like someone was controlling most of De Jure France or something). The new king doesn't hold many titles at all (only King of France and county of Paris) so he can't have been very powerful before this sudden power transition. Anyone has an idea what happened?

 

[Tapscott]

This luckily didn't happen to me, but to an AI France and I'm trying to figure out what happened.

Here's the situation: Navarra was pretty strong in the Iberian peninsula, but France also held some land in central Spain. Then France attacked Navarra for its claim on Seville, and Navarra called me (England) into the war. Together we had little trouble in defeating the French, and so they lost.

Less than a month later, I get the message that "King Gargamel II of France has usurped the title Kingdom of France from King Gargamel I of Andalusia." Apparently Gargamel I held two king titles, of which France was usurped away from him, and now he has only Andalusia left. But how did that happen? France just looked normal to me (not like someone was controlling most of De Jure France or something). The new king doesn't hold many titles at all (only King of France and county of Paris) so he can't have been very powerful before this sudden power transition. Anyone has an idea what happened?

My guess is that a successful faction war/demand overthrew the old king and put the claimant, the new king, on the throne of France.

 

[Taylor]

My guess is that a successful faction war/demand overthrew the old king and put the claimant, the new king, on the throne of France.

Ah so you mean the old king actually accepted a faction ultimatum? I hadn't thought of that, I thought the AI always chooses war.

 

[Avisian]

Not always. Traits modify this, the base chance is 10% accept 90% war.

Craven, humble etc increase accept odds.
Proud, Wroth etc increase war odds.
Having more then 100% of liege troops increases accept, less increases war odds.