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