One of their Famous albums

Crosby, Stills, Nash & Young ("CSNY") began performing together in 1969 as the first true folk-rock 'super-group' formed by four guitar-playing singer-songwriters from other popular bands. David Crosby came from The Byrds; Stephen Stills and Neil Young came from Buffalo Springfield; and Graham Nash was a member of British pop band The Hollies. Originally just a threesome