Symphonic rock artists in the late 1960s had some chart success, including the singles "Nights in White Satin" (the Moody Blues, 1967) and "A Whiter Shade of Pale" (Procol Harum, 1967). The Moody Blues established the popularity of symphonic rock when they recorded "Days of Future Passed" together with the London Festival Orchestra, and Procol Harum began to use a greater variety of acoustic instruments, particularly on their 1969 album "A Salty Dog". Classical influences sometimes took the form of pieces adapted from or inspired by classical works, such as Jeff Beck's "Beck's Bolero" and parts of the Nice's "Ars Longa Vita Brevis". The latter, along with such Nice tracks as "Rondo" and "America", reflect a greater interest in music that is entirely instrumental. "Sgt. Pepper's" and "Days" both represent a growing tendency towards song cycles and suites made up of multiple movements.