The Masurians evinced strong support for Germany during World War I. In 1920 the League of Nations supervised the East Prussian plebiscite - with British, French and Italian troops stationed in Masuria - to determine the new border between the Second Polish Republic and German East Prussia. The plebiscite was organized by the local German authorities. Polish ethnographer Adam Chętnik stated that the German authorities performed abuses and falsifications during the plebiscite, and Stefan Berger writes that the Masurians were subjected to huge psychological pressure and physical violence by German side to vote for Germany. Kossert admits irregularities during the referendum, but asserts that in general, its results truthfully reflected the overwhelmingly pro-German sentiment in southern East Prussia. In Masuria proper the vast majority (99.32%) opted to remain in Prussia. Attempts to create schools teaching Polish in interwar Germany were met with terror and violence.