After World War I, the Entente set the border between these two countries at the Foch line, whichcaused a conflict between them known as the Sejny Uprising. One of these countries sent Henry ofMasovia to negotiate the Ostrow Agreement with the other. Collaborationist forces in one of thesecountries massacred over fifty-thousand civilians in the Ponary massacre. The head of one of thesecountries instigated Zeligowski's Mutiny in the other. The combined forces of these two nationskilled (*) Ulrich von Jungingen and defeated his Teutonic Knights at the 1410 Battle of Grunwald. Otherfriendly acts between these nations include the Union of Krewo and the Union of Lublin, which wasenacted by Sigusm
After World War I, the Entente set the border between these two countries at the Foch line, whichcaused a conflict between them known as the Sejny Uprising. One of these countries sent Henry ofMasovia to negotiate the Ostrow Agreement with the other. Collaborationist forces in one of thesecountries massacred over fifty-thousand civilians in the Ponary massacre. The head of one of thesecountries instigated Zeligowski's Mutiny in the other. The combined forces of these two nationskilled (*) Ulrich von Jungingen and defeated his Teutonic Knights at the 1410 Battle of Grunwald. Otherfriendly acts between these nations include the Union of Krewo and the Union of Lublin, which wasenacted by Sigusmund II Augustus. For 10 points, name these countries that formed a commonwealthwhich had joint capitals at Warsaw and Vilnius.
After World War I, the Entente set the border between these two countries at the Foch line, whichcaused a conflict between them known as the Sejny Uprising.
Poland and Lithuania