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