Most, polish schools were closed, and those that remained open saw their curricula altered significantly. 10 The occupying powers destroyed Polish book collections, including the Sejm and Senate Library, the Przedziecki Estate Library, the Zamoyski Estate Library, the Central Military Library, and the Rapperswil Collection. 27 Polish flags and other symbols were confiscated. 50 Mere possession of such books was illegal and punishable by imprisonment. This was accomplished through deliberate tactics such as police raids on schools, police inspections of student belongings, mass arrests of students and teachers, and the use of students as forced laborers, often by transporting them to Germany as seasonal workers. Contents, background edit, main articles: Partitions of Poland, Invasion of Poland (1939), History of Poland (19391945), and, occupation of Poland (19391945 in 1795 Poland ceased to exist as a sovereign nation and throughout the 19th century remained partitioned by degrees between Prussian, Austrian and Russian. 101 There, writers and editors faced similar dangers: for example, almost the entire editorial staff of the underground satirical paper Na Ucho was arrested, and its chief editors were executed in Kraków on ( Na Ucho was the longest published Polish underground paper devoted. 109 Theater was also active in the Jewish ghettos and in the camps for Polish war prisoners. 118 The 10th Underground Tournament of Poetry was held during the Uprising, with prizes being weaponry (most of the Polish poets of the younger generation were also members of the resistance).