I've finally managed to carve out a decent kingdom in CK2, including Wales, Ireland, Brittany, Galacia and some bits of Scotland.
I have two King titles- the Kingdom of Wales (primary) and the Kingdom of Ireland. Brittany and Galacia aren't actually kingdoms because of the risk of losing the titles through elective succession.
Unfortunately, England managed to get a claim on Wales and are now invading. I'm probably going to lose the war.
What will I lose when I lose the kingdom of Wales? Will my vassals in Brittany and Scotland swear fealty to England? What about my Irish vassals?