City (pop., 2000 est.: 574,896), west-central Poland. Located on the Warta River, Poznan is one of the oldest cities in Poland, dating from the 9th century AD. It reached the height of prosperity as a trade centre from the 15th to the 17th century but declined after the Second Northern War. In 1793 Poznan was annexed to Prussia, intensifying a Germanization that had begun in the 13th century. In 1918 it reverted to Poland. During World War II it was occupied by the Germans and suffered extensive damage. Rebuilt after the war, it has become the administrative, industrial, and cultural centre of western Poland. It is also an academic centre with scientific and literary institutes. Its varied industries include textile mills, metallurgical works, and chemical plants.