Bochum dates from the 9th century, when Charlemagne set up a royal court at the junction of two important trade routes. It was first officially mentioned in 1041 as Cofbuokheim in a document of the archbishops of Cologne. Originally, it may have meant "Brookhome" or "Bacheim" and later seems to have gained the notorious reputation of "Bookhorn" or "Horn Book". In 1321, Count Engelbert II von der Marck granted Bochum a town charter, but the town remained insignificant until the 19th century, when the coal mining and steel industries emerged in the Ruhr area, leading to the growth of the entire region. The population of Bochum increased from about 4,500 in 1850 to 100,000 in 1904. Bochum acquired city status, incorporating neighbouring towns and villages. Additional population gains came from immigration, primarily from Poland.
After the war, the new state of North Rhine-Westphalia was established, consisting of the Rhineland and Westphalia. Bochum is located in that state.
In the postwar period, Bochum began developing as a cultural centre of the Ruhr area. Between 1960 and 1980, the coal mines all closed. Other industries, such as automotive, compensated for the loss of jobs. The Opel Astra is assembled at the Opel Bochum plant; however, by 2009, the factory was in serious financial difficulties. In 1965, the Ruhr University was opened, the first university in the Ruhr area and the first to be founded in Germany since World War II. Since the seventies, Bochum's industry has moved from heavy industry to the service sector.
In the course of a comprehensive community reform in 1975, Wattenscheid, a formerly independent city, was integrated into the city of Bochum. A local referendum against the integration failed. In 2007, the new synagogue of the Jewish community of Bochum, Herne und Hattingen was opened. In 2008, Nokia closed down its production plant, causing the loss of thousands of jobs, both at the plant and at local suppliers. 20,000 people
