Kassel (käsˈəl) [key], city (1994 pop. 202,160), Hesse, central Germany, on the Fulda River. It is an industrial, rail, and cultural center. Manufactures include textiles, optical and precision instruments, locomotives, and motor vehicles. Kassel was mentioned in 913 and was chartered in 1198. It became (1567) the capital of the landgraviate of Hesse-Kassel (raised to an electorate in 1803; see Hesse). Kassel also was the capital of the kingdom of Westphalia (1807–13) under Jérôme Bonaparte. After Electoral Hesse and Nassau passed (1866) to Prussia and were united as the province of Hesse-Nassau, Kassel was made the capital. As a center of German airplane and tank production in World War II, Kassel was severely damaged by Allied air raids, and many historic buildings were destroyed. Kassel has several important museums. International exhibits ("Documenta") of modern art are held every five years in the city and are considered the world's largest art exhibitions. A former spelling is Cassel.