See Brythonia Rise!(formed by brittany, MEIOU you have to own/vasslize/PU brittany, scotland,wales,ireland)
Started off as brittany, ate the stab hit and went into ireland. Took one province there, got conquest missions for 3 other parts of ireland. Luckily france was busy elsewhere. As for england they were invaded by castille,scotland and denmark(who would take tyrone and wessex) who wiped out their armies and fleet. Then england got nailed with a peasant war. By the time id cleaned up in ireland(had connacht vassalized, tyrone owned by denmark) england had no armies and was half rebel occupied. Ate another stability hit and i launched C-Day. After landing in wales, i annexed wales and one other province. At the time my king was called artur so i save game editted and game him "arthur" as his name

Over the next couple decades i kept founding rebels and pushing into england. Scotland took a decent bit of england then i forced a PU on scotland.I got insanely lucky and managed an alliance with france. The last 20 years or so have seen me consolidating and starting my colonization. Thus far i have a couple islands in the lesser antilles and the greatest new world province of timucua.
Other notes, the ming are slowly eating the hordes
Timurids stayed alive and culture changed to persian somehow. Thus the mega huge persia to the east.
Blue horde(golden horde) conquered some of the other hordes to the east, formed the mongol empire although they're slowly being devoured by persia
Yes thats firenze(florence/tuscany) in hungary
Im also insanely happy that turkey is actually doing very good for once. Although austria didnt do anything for like 80 years until they finally mostly ate styria
See Moscowvy rise!
Edit:ive been playing mostly handsoff with europe, baring some fighting in france to keep them upright i want to see how europe plays out. Im renaming all of the provinces into a breton/irish/welsh name. Im going to leave SE england to england, that can be their land and i'll ignore them(my RP i suppose). Once i inherit scotland, im going to most likely release scotland as a vassal and leave them there, freedom(ish) for scotland