Here is the full list of all 11 Manor Lords achievements.
Beat "Restoring the peace" with Mercenary units only.
Finish the "Restoring the peace" scenario
Defeat the baron in the "Restoring the peace" scenario.
Reach 100% approval in a "large town".
Destroy a squad of brigands with a squad of militia in a non battle game mode.
Get to a "small town" settlement level without hunting or gathering berries.
Employ 24 retainers.
Face the winter and have your settlers not abandon you.
Change the church bell sound.
Big success!
Beat "Restoring the peace" on "Challenging" difficulty preset.