What types of music became rock?

Answer 1

In the 1960s, Rock emerged out of Rock 'n' Roll. Rock musicians, who started out playing Rock 'n' Roll and Blues, experimented with the potential of heavily amplified instruments and studio technology. The Beatles' music is a good example of the evolution of the style. The label "Rock 'n' Roll" was shortened to "Rock" as they adopted rhythms which were very different from the simple dance beat.

The history goes back much farther than that, however.

Rock 'n' Roll started in the early 1950s as a spinoff of Rhythm & Blues (R&B). R&B developed in the 1940s from Swing. Swing, which was popular in the 1930s, developed out of Jazz. (In the 1920s, what they called "Jazz" was rocking dance music; it was not until the 1940s that jazz took a detour into experimental forms like bebop, from which it never fully recovered). The Jazz of the 1920s had developed out of Ragtime.

Quoting from Wikipedia,

...during a nationwide broadcast of the Bing Crosby (radio) Show, Crosby said, "We have as our guest the master of swing and I'm going to get him to tell you what Swing Music is." He asked Louis [Armstrong] to explain it. Louis said, "Ah, swing, well, we used to call it ragtime, then blues-then jazz. Now, it's swing. White folks yo'all sho is a mess. Swing!"

Answer 2

Im not completely sure on your question, but ACDC was once classified as a METAL band and is now because the of the metal these days ACDC is not 'hard enough' and is classified as rock now.