I’ve been ranting and raving about underpinning a lot lately. Here’s an example of a proper corset/garment match up.
This is a 1905 Wedding corset, and a 1910 wedding gown to accompany it. This style (narrow waist, roomy bosom, exaggerated hips) of corset would have been worn beneath that Wedding dress.
They also wore padding in this time period. Bosom pads that lent women the ‘pigeon’ breasted look, and some wore hip pads as well (considerably more form fitting than the earlier padded bustles, but a similar principle).