Procol Harum (/ˈproʊkəl ˈhɑːrəm/) is an English progressive rock band formed in 1967. Their best-known recording is their 1967 hit single "A Whiter Shade of Pale", considered a classic in popular music and one of the few singles to have sold over 10 million copies. Although noted for their baroque and classical influence, Procol Harum's music also embraces the blues, R&B, and soul.
Procol Harum returned to success on the record charts in the following years with a symphonic rock sound, often backed by symphony orchestras. At this it was one of the first groups to achieve success; Procol Harum Live: In Concert with the Edmonton Symphony Orchestra was a No. 5 gold album in the US in 1972, as well as reaching No. 48 in Britain. "Conquistador" (a track from their first album, re-charted for accompaniment by the Edmonton Symphony in 1971) was a hit single in 1972, getting to No. 16 in the US and No. 7 in Canada, whilst reaching No. 22 in the UK.