Although Robin and his brothers were not necessarily the longest continuously performing rock group to come out of the British invasion beginning in 1964, they came pretty close. Originally from the Isle of Man, they were managed by Brian Epstein, who managed some other group. (And just who were those other guys?)
Like in other brother/sister/family groups, the harmony of the Bee Gee's was tight and close and was more palatable to the more traditional listeners than much of what was to come out of the 60's. Certainly much of the success of the Gibb brothers was due to the immediately recognizable high tenor of Robin.
At one time there was a great website put up by the Bee Gees Fan Club. Alas, it seems to have disappeared.