Do you know the band "Yes"? From the late 1960s to the mid 1970s, there were rock bands, who played music called "Progressive Rock", such as Pink Floyd, King Crimson, Yes, and Emerson, lake & Palmer.
The black R&B musicians, such as Little Richard and Chuck Berry, began to play Rock and Roll in America in the mid 1950s. The white musicians, such as Elvis Presley and Jerry Lee Lewis, imitated them and made Rock and Roll one of the most popular styles of pop music.
In the 1960s, the Beatles pursued the potentialities of Rock, (At that time, the word "Rock and Roll" was replaced by the word "Rock") and showed that Rock wasn't just dance music and that it could also be serious music.
I think that the 1970s was the golden age of Rock. Many styles of Rock, including "Progressive Rock", flourished. The bands, who played "Progressive Rock", wanted to make Rock serious music. They thought of it as "the progress of Rock".
But what is "progress" in Rock music?
Inamoto, one of my friends told me that this video was really amazing.
I don't think that Jerry Lee Lewis played "serious music". But both of Yes and Jerry Lee Lewis are quite enjoyable. I can't say that Yes is more "progressive" than Jerry Lee Lewis.
I wrote in the entry "The Song for All of the Stupid Boys in the World" as follows.
I think that rock music isn't contemporary music now either. Hip hop killed Rock music in the 90s, and Nirvana was the last band that created new rock music.
Nirvana weren't called "progressive" but "alternative". By the 1990s, people had already stopped believing in the "progress" of Rock.