In campaigns with several factions in Viking Invasion, among them the Vikings and the Saxons, I have had problems with civil wars starting. They don't seem to start for any obvious reason. The campaigns have generally got well and smooth until the civil war erupts, and I have not had too many disloyal generals.

What can I do to prevent this? I find that civil wars basically ruin my campaigns, as they are generally followed by additional civil wars. Makes it impossible to win a campaign.

I play on normal difficulty.