Assertion: progressive rock | /r/HasProperty | predicated on progressivepop groups
Facets:
value: from the 1960s
type: TEMPORAL
Source sentences:
text: Progressive rock was predicated on the "progressive" pop groups from the 1960s who combined rock and roll with various other music styles such as Indian ragas, oriental melodies and Gregorian chants, like the Beatles and the Yardbirds.