The '50s progression (also known as the "Heart and Soul" chords, the "Stand by Me" changes,[1][2] the doo-wop progression[3]: 204 and the "ice cream changes"[4]) is a chord progression and turnaround used in Western popular music. The progression, represented in Roman numeral analysis, is I–vi–IV–V. For example, in C major: C–Am–F–G. As the name implies, it was common in the 1950s and early 1960s and is particularly associated with doo-wop. The first popular song to use the progression was "Blue Moon", written in 1934. This inspired "Heart and Soul" in 1938.