Waging war in Crusader Kings 3 is an art form, and your dynasty’s military innovations are the brushstrokes that decide who rules the map. From crushing peasant revolts to dismantling rival empires, the right innovations can transform your army from a ragtag levy into a professional killing machine. But with dozens of unlocks spread across multiple eras, knowing which ones actually make a difference can be the difference between a swift victory and a century-long embarrassment.
Let’s break down the best military innovations for war in CK3, era by era, with a look at how they change your campaigns, your troops, and your sanity.
Tribal Era – Surviving the Chaos
When you’re still counting cows as currency, survival is the name of the game. Tribal warfare is brutal, and every innovation counts.
Key Innovations:
- Battlements – Unlocks early Fortifications and Siege Weapons. Keeps raiders out and gives your wars some much-needed structure.
- Motte – Adds a proper Castle to your domain. Goodbye wooden walls, hello stone towers.
- Bannus – Allows you to raise levies faster. In tribal wars, speed is survival.
- Casus Belli Innovations (e.g. Bellum Justum) – Reduces Prestige cost for wars. Because every prestige point counts when you’re already broke.
Best Use: Focus on Fortification and Levy speed techs first. You’ll lose plenty of battles early on, but at least you’ll look respectable doing it.
Early Medieval Era – The Rise of Real Armies
This is where things get interesting. With early medieval innovations, your armies stop being angry mobs and start resembling professional forces.
Key Innovations:
- Mangonel – Early siege weaponry that speeds up conquests dramatically.
- Men-at-Arms Regiments – Expands the number and size of your Men-at-Arms units. Essential if you’re tired of seeing your levies fold.
- Armoured Footmen and Crossbowmen – Upgraded unit types that crush older compositions.
- Casus Belli: De Jure Wars – Makes expanding your realm faster and cheaper.
Best Use: Prioritise Men-at-Arms and Siege techs. Conquests become quicker, wars shorter, and rebellions less tedious.
High Medieval Era – Empire Building and Efficiency
At this stage, you’re likely a major power or at least pretending to be. The focus shifts from survival to dominance.
Key Innovations:
- Trebuchet – Siege engines that make castles feel like sandcastles.
- Hereditary Rule – Not purely military, but keeps your realm stable between wars.
- Knighthood – Boosts Knight effectiveness and adds serious punch to battles.
- Standing Armies – Reduces maintenance costs for Men-at-Arms. You’ll thank yourself later when your empire starts draining gold faster than it earns it.
Best Use: Combine Knighthood with Standing Armies. It makes your elite forces terrifyingly efficient and affordable enough to keep around.
Late Medieval Era – The Age of Destruction
By now, your dynasty is ancient, your enemies are few, and your patience is thin. These innovations are less about surviving and more about absolute domination.
Key Innovations:
- Bombards – The best siege weapon in the game. If it’s not fortified, it’s falling.
- Plate Armour – Boosts Knight effectiveness even more. Your champions turn into walking tanks.
- Military Academies – Improves Men-at-Arms and Commander quality. Your generals actually start to feel like professionals rather than noble amateurs.
- Royal Prerogative – Allows maximum crown authority, perfect for holding vast realms together during endless wars.
Best Use: Stack Bombards, Military Academies, and Plate Armour. At this point, you’re not fighting wars, you’re conducting exterminations.
Honourable Mentions
Not every innovation directly affects war, but a few give indirect boosts that can turn a losing campaign around:
- Guilds – Improves income to fund more Men-at-Arms.
- Divine Right – Lets you claim titles more easily. More wars, less paperwork.
- Heraldry – Adds stability and inheritance control, reducing messy succession wars.
Strategy Tips
- Prioritise Your Culture’s Focus: Some cultures have unique innovations (like Norse’s Longships or Byzantine Cataphracts). Don’t ignore them.
- Hybridise Cultures: Mix and match to gain innovations faster. Especially useful if your native tech is lagging behind.
- Always Check Era Progress: Advancing eras early through cultural fascination can give you access to devastating techs before your neighbours.
Seven Swords Takeaway
War in CK3 is about momentum and technology. The right innovations turn chaos into conquest, and a strong cultural strategy ensures your military stays ahead of its time. Whether you’re a tribal warlord or a late-medieval emperor, these upgrades decide who writes history and who becomes its footnote.
