EU4: Are Marches Worth It?

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Turning a vassal into a march can be an excellent idea if you’re in any of these three situations:

  1. Your vassal has strong military ideas
  2. Your vassal’s geography includes mountains, hills, and other defensive terrain
  3. Your vassal is next to a powerful rival

Any of those things will affect the value of marches in their two purposes: for offense, and for defense. So marches can be worth it, but generally in specific situations — and we’ll cover them in this guide.


Marches: Brief Pros & Cons

Pros Cons
  • Marches receive various military modifiers.
  • They can field and maintain larger forces than your regular vassals.
  • They’ll contribute 20% of their force limit to your own.
  • They don’t pay you any vassalage fees.
  • You’re prohibited from annexing them. You can only do so if you revert them back into a vassal, which penalizes you with -1 stability and -50 opinion.

Tip: The Diplomatic idea group removes the stability penalty and drastically reduces the opinion hit to just -10.


Purposes of a March


#1: For Offense

Vassals with strong army ideas excel even further if you make them a march. You’re essentially sharpening their strengths and using them as a spearhead against your enemies.

Subject Interactions for Marches / Europa Universalis IV
Subject Interactions for Marches

Since they’re controlled by the AI, marches allow less micromanagement on your part.

A couple of examples include:

  • In the Province UI, you can mark enemy provinces as your march’s objectives. They’ll prioritize occupying those if possible.
  • In the Subject Interaction tab, you can adjust their Military Focus, which dictates their behavior during war. You can have them focus on sieging provinces or have them hunt down enemy armies.

Note: This type of march loses its usefulness if they take too long to reach your enemies. If they need more than a year to get to an objective, consider reverting them back into a vassal instead.


#2: For Defense

Marches with difficult terrain make ideal buffer states.

They can act as sponges, absorbing your enemy’s time and manpower.

A great example would be the Georgian Orthodox nations around the Caucasus. They have these characteristics:

  1. Their starting national traditions boosts their fort defensiveness
  2. Their geography is mostly mountains
  3. Their region is a natural choke point
  4. They’re surrounded by large bellicose countries

If you have a chance to subjugate any of them, turn them into a march and feed them provinces.

They’ll be useful against the Ottomans, the Russians, and everyone else in that region.

Almost Everyone Here Have Great Defensive Ideas / EU4
Almost Everyone Here Have Great Defensive Ideas
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Louie Nelson Zafico

As a frustrated otter who dreams of getting published, Louie instead wastes his life cuddling his cats. He spent his childhood playing Suikoden, grew up with Total War, and matured (somewhat) with EU4. He hopes to someday find a geopolitical JRPG with the 4X systems of a Paradox game.