The name "Kleff" probably derives from Middle Dutch "clef", "clif" 'cliff, bluff', referring to the promontory on which the Schwanenburg castle was constructed. Since the city's coat of arms displays three clover leaves (German "Klee", Low German "Kliev"), the city's name is sometimes linked by folk etymology to the clover, but the corresponding Dutch word is "klaver". Notably, Kleve was spelled with a "C" throughout its history until spelling reforms introduced in the 1930s required that the name be spelled with a "K". In 2008, the CDU announced its intention to return the name to its original spelling.