Here is the full list of all 19 Fit For a King achievements.
Ride a horse.
Ordain the bear.
Meet your rival at the summit.
Outspend your rival at the summit.
Make your rival cry.
Reform the church.
Meet the leader of a distant land.
Play an anachronistic song.
Marry a princess.
Get an evaluation of your rulership.
Fill your chamber with spouses.
Fill your jail with prisoners.
Marry an inanimate object.
Have a swashbuckling adventure.
Get a suit of gold.
Get a suit of gold for a monkey.
Gain 5xp.
Get assassinated.
Conquer the known world.