Has there ever been a situation where the following conditions applied:

At the same point in time

  • A is actively war with B on battlefield 1
  • other troops of both sides work together* against C on battlefield 2

*= not just "happen to target the same object" but "actively communicating or planning on each other's support".

The closest that comes to my mind was Germany and Russia when they took Poland but at this point they haven't been in a real war yet.

Another potential I am seeing is in the Syria conflicts as some groups stated they aren't even sure who they are fighting for/ against.

This is somewhat based on Has there ever been a truly multi-sided war? except for the "collaboration at the same time" part.

  • 3
    Welcome to History.SE @user2161301 Could you edit your question to clarify where you've searched and what you found already, complete with links and references, and context if applicable? In particular, please let us know what you find missing or unclear about the Wikipedia entry on the topic, if one exists. This allows those who might want to answer to do so without needing to redo the work you've already done. You might find it helpful to review the site tour and help center and, in particular, How to Ask. I think this question has been asked. – MCW Jan 27 '20 at 2:22
  • 1
    I believe what you describe is very common for situations when one party is about to change sides in the war. This includes the WW2 example in @JoseCarlosSantos answer, but you can also look at Finland, Italy, Romania, and French Algeria changing sides at the end of WW2. Also: Jordan warned Israel in the Yom Kippur war. Württemberg and Saxony changed sides and abandoned Napoleon during the battle of Leipzig. In antiquity, troops changing sides was a major problem, so the general would put his most unreliable forces somewhere where they could not easily change sides or withdraw. – 0range Jan 27 '20 at 12:09
  • Hey @MarkC.Wallace , is this an automated response? Nothing that you said applies to my post. – user2161301 Jan 27 '20 at 16:26
  • The community prefers to use a standard wording to respond to questions that don't show preliminary research. Can you show where you documented your preliminary research? – MCW Jan 27 '20 at 16:47

On the 9th October 2019 Turkey started Operation Peace Spring, invading north-eastern Syria. In response the Syrian Democratic Forces (SDF) joined forces with the Syrian Arab Army (SAA) to respond to the invasion. The SDF (as well as other groups) and the SAA have been engaged over much of the country since the 2011 uprising, and are currently engaged in Idlib.


A possible example would be the Battle for Castle Itter, a World War II battle which took place on the 5th May 1945, in which American and German troops fought side by side against other German troops.

  • darn, you beat me to it. I believe there were a few similar incidents during the later stages of WW2 in Europe. – jwenting Jan 27 '20 at 11:36

The Chinese Civil War comes to mind, since there two chinese factions (Nationalists and Communists) and one foreign faction, i.e. the Japanese. The alliance between Nationalists and Communists wasn't a very close one.

However, I am not quite sure whether this conflict matches the battlefield 1 & battlefield 2 requirement.

Not the answer you're looking for? Browse other questions tagged or ask your own question.