OK, so how about "fall of empire" as taking place 1956-1984? (3 decades sounds long to me, but it would allow a royal wedding and the recovery of Las islas Mal

OK, so how about "fall of empire" as taking place 1956-1984? (3 decades sounds long to me, but it would allow a royal wedding and the recovery of Las islas Malvinas to be the last gasp of empire?)