The Poland-Romania War started on the 24th May 2011.
The war was an outgrowth of the Fourth Balkan War, which had resulted in the wiping of Romania by ONE forces. After some weeks, Romania had began to regain its territories and slowly launched its own counter attacks against neighboring Hungary, as well as taking part in the EDEN invasion of Serbia.
Meanwhile, Poland declared war against Ukraine during the Ukraine-Turkey War and as Ukrainian territories fell to Polish occupation, Romanian territories became accessible to a Polish invasion.
Romania had been warring with Hungary since the beginning of World War V and by securing territories along the northern border of Romania, Poland began to enter into in the Hungary-Romania conflict to assist its ONE ally.