Me, being annoyed at the civil wars going on once every 20 years, I decided to purge my realm.
My King was old, had piety, and a little gold for mercenaries in case anything happened.
I began by imprisoning the heir of every single duchy and county. Roughly 4 people escaped.
Then, I began imprisoning Dukes, and banishing. Luckily for me, my overall intrigue was pretty high, and about 6 of my dukes rebelled. I got them, imprisoned, and banished. I am now at a point, 3 years later as my son, controlling every title in Britannia, with 30k gold, and 15 rebelling bishops/mayors left.
Time to sit back, upgrade some of my expanded demense, and redistribute lands to loyal, freshly invited to court Englishmen, and give them only 1 county each.
Edit: Now my King has just died, and my son, got married to amazing stat twin sister.
As for those four people that escaped, well, I have gold, and an assassinate option..