MusicXML scores for euphonium by Nico Sieffers

Christa Päffgen ([ˈkʁɪsta ˈpɛfɡən]; 16 October 1938 – 18 July 1988), known by her stage name Nico, was a German singer, songwriter, actress, and model. She had roles in several films, including Federico Fellini's La Dolce Vita (1960) and Andy Warhol's Chelsea Girls (1966). Reviewer Richard Goldstein describes Nico as "half goddess, half icicle" and writes that her distinctive voice "sounds something like a cello getting up in the morning."

At the insistence of Warhol, Nico sang on three songs of the Velvet Underground's debut album The Velvet Underground & Nico (1967). At the same time, she started a solo career and released Chelsea Girl (1967). Nico's friend, Jim Morrison, suggested that she start writing her own material. She then composed songs on a harmonium, not traditionally a rock instrument. John Cale of the Velvet Underground became her musical arranger and produced The Marble Index (1968), Desertshore (1970), The End... (1974) and other subsequent albums.

In the 1980s, Nico toured extensively in Europe, United States, Australia and Japan. After a concert in Berlin in June 1988, she went on holiday in Ibiza to rest and died as the result of a cerebral haemorrhage while cycling in extremely hot weather.