Here is the full list of all 21 Mount & Blade: With Fire and Sword achievements.
Finish the Polish Commonwealth's main storyline quest "The Deluge"
Successfully blow a hole in a castle/town wall before a siege.
Build three upgrades in a single town/castle you control.
Tend to your army's illnesses, five times, by resting or feeding them.
Start any main storyline quest found in the three main factions.
You've made 1,000,000 thaler from using trade caravans.
Complete the summer feast quest found in any village on the eastern side of the map.
Buy drinks for everyone at a bar.
Kill 50 enemies with grenades.
Keep 10 bundles of velvet in your inventory.
You've made 100,000 thaler from using trade caravans.
Using any firearm; kill 100 enemies.
Earn 3,000 thaler in profit from a single caravan trade.
Build a wagon fort from the camp menu.
Get in a bar fight.
Customise your mercenaries' equipment using the mercenary camp.
Finish the Cossack Hetmanate's main storyline quest "The Black Mace"
Finish the Moscovite Tsardom's main storyline quest "The False Dmitry"
Join the Crimean Khanate and eliminate all other factions.
Join the Kingdom of Sweden and eliminate all other factions.
As any faction; conquer the map and eliminate all other factions.