Has anyone managed to conquer/convert England or France to Breton culture?

[Sleight of Hand]

Just curious, as I do like the idea of attempting this but imagine it's incredibly difficult.

Brittany and Cornwall are both Breton culture, and so going by the standard conversion rules it ought to be possible to extend Breton culture into England and France. The furthest I got was in a 1.05 or 1.06 game where I managed to form the kingdom of Brittany as a de Rennes duke and vassalize the duke of Somerset after he'd won a successful independence war.

Has anyone managed to wipe out Saxon/English or Frankish culture in this manner, or at least really push it back?

 

[Heartsbane]

Unfortunately not. In 1.06 I did seize France in an Invasion as the Kingdom of Brittany but I never got Breton culture to spread outside of Anjou. Culture spread was kinda wonky in 1.06 though.

 

[Kamahawk]

In one of 1.06 games I managed to covert normandy and flanders to Breton as well as paris. In the same game on the other side of the channel about 1/3 of england was breton (mostly on the sothern side).

 

[Spartanlemur]

Just going to throw in that I think culture conversion has been fixed. As the Roman Empire, around 150 years in most of Africa is Greek alongside the majority of the Mediterranean and Southern/Mid Italy.

 

[Ekstrakt]

I've made an attempt.
Started as a Breton count, usurped the duchy. Inherited Aquitaine and all it's vassals. Blackmailed the French king and pushed claims for southern England.
I managed to convert a good portion of northern France, i.e. Normandy and Maine and so forth, but not England.

This is one of the quite interesting scenarios though, because it is entirely possible to convert both realms to Breton. Such is the way for Caithness and it's Norwegian culture as well, I often aim for a Norwegian Scotland.

 

[Yenzen]

The new version has greatly sped up culture conversion. However you can improve the speed of this conversion by getting vassals with high stewardship (and also yourself, in your own demesne).

 

[Sleight of Hand]

Such is the way for Caithness and it's Norwegian culture as well, I often aim for a Norwegian Scotland.

Yes, I've succeeded in turning Scotland both Saxon (as Gospatric of Lothian) and Norwegian (as Pål of Orkney) at one point or another, but I've never been able to spread Breton culture very far. It's hard enough defending against the Normans (they always fabricate a claim on Rennes and then declare war, destroying me with their super cavalry and ready-upgraded holdings) but even if I manage to take Cornwall and chunks of Ireland and Wales I still get flattened by the French. You just can't make up the numbers.

I'm not a very good player, though, so I just thought some of you guys may have anecdotes or screenshots. It must be possible, but I agree that the whole culture system was bugged before 1.07 so I suppose it's only recently that such a feat will have been possible.

 

[Yenzen]

There are paths:

1: Participate in the reconquest of Spain and start gathering titles from the scattered domains in Ireland, use the levies to your advantage.
2: Melt into France and take it over from the inside
3: Marry a French Princess and murder her way to the throne, inherit France, then destroy it. Edit: agnatic, nevermind. You can do it for England though.
4: Save up a huge sum of money, and then wait for the French to become unpopular with the pope, and invade it - siege as many province's capitals as possible and put Breton nobles in charge of them.