Adam Mickiewicz University (Polish: Uniwersytet im. Adama Mickiewicza) is one of the major Polish universities, located in the city of Poznań in western Poland. It opened on May 7, 1919, and since 1955 has carried the name of the Polish poet Adam Mickiewicz. The university was ceremonially opened on May 7, 1919 (the 400th anniversary of the foundation of Poznań's Lubrański Academy). It was originally called Wszechnica Piastowska ("University of the Piasts" – wszechnica being a less common Polish word for "university"), and in 1920 was renamed Uniwersytet Poznański ("Poznań University"). For the first 20 years it educated students in law, economy, medicine, humanities, mathematics, natural sciences, agriculture and forestry. In 1920 famous sociologist Florian Znaniecki founded the first Polish department of sociology at the university, one of the first such departments in Europe. In the same period of the university's history, botanist Józef Paczoski founded the world's first institute of phytosociology. After the invasion of Poland, Poznań was annexed by Germany and the University was closed by the Nazis in 1939.