…18th century “rumps” and false bums”, but the application of new technologies in metal working, overuse of baleen and horsehair and so the new introduction of synthetics for padding and structures, made them very different than those of the prior century, although the overall result might have been very similar.
(Photos: (left) the 1760’s “false rump” or “bum pad” looks a lot like the (right) 1880’s “padded bustle pad”)