The university's central administrative building is Collegium Minus, on the west side of Adam Mickiewicz Square at the western end of the street Święty Marcin. (This is one of a group of buildings, including the Imperial Palace, built in the first decade of the 20th century while Poznań was still under German rule; it originally housed a Royal Academy.) Adjoining this is the Aula, which is frequently used for ceremonies and for classical music concerts, and Collegium Iuridicum (accommodating the law faculty). Some teaching takes place in Collegium Maius, another of the aforementioned group of buildings (on ul. Fredry), although this is mainly used by the medical university. Other buildings in the city centre include former communist party headquarters on Święty Marcin, Collegium Novum (used mainly for language teaching) on Al. Niepodległości, and the university library on ul. Ratajczaka.