But where did this symbol originate?
The dove and the olive branch used to symbolize peace until mid twentieth century when the peace sign as we know it became the world recognized symbol for peace.
It was initially designed for the British nuclear disarmament movement by designer Gerald Holtom, the design was completed on February 21st 1958 for the 4 April march planned by the Direct Action Committee against nuclear war (DAC). The symbol was later adopted by the Campaign for Nuclear Disarmament, then by the Anti-War movement in 1960 and then by the counterculture and finally by our popular culture.
The peace sign flag first became known in the US in 1958 when Albert Bigelow, a pacifist protester, sailed his small boat outfitted with the CDN banner into the vicinity of the nuclear test.
More on the history of the peace sign at wikipedia.org