Assertion: rock's music | /r/AtLocation | the u.s.
Facets:
value: by the mid-1960s
type: TEMPORAL
value: prior to its development
type: TEMPORAL
Source sentences:
text: According to journalist Greg Kot, "rock and roll" refers to a style of popular music originating in the U.S. in the 1950s prior to its development by the mid-1960s into "the more encompassing international style known as rock music, though the latter also continued to be known as rock and roll.