Pro-Swedish Poland
The Swedish invasion of Poland, also known as Charles XII's invasion of Poland or the Polish front of the Great Northern War, was a conflict in eastern Europe overshadowed by the ongoing Great Northern War fought between Sweden, on the one side, and Russia, Denmark-Norway, Saxony and the Polish–Lithuanian Commonwealth on the other side. The Polish front was a major part of the greater conflict, and it included some decisive battles in favor of the Swedes that contributed to the length of the war (21 years).