Do you mean when did it first become fashionable to have fashion repeat itself (Eg: 80's does 50's trend, current 2013-14 90's love trend?)

Good question. The earliest instance I can really come up with, without doing research, is the Egyptian craze of the 1910s-1920s. But, I'm sure throw back fashion happened at some point prior to that. The next one I can think of is toga parties beginning in the 50s which were a throwback to ancient Greek and Roman fashion.