Let’s take a look at a few items that helped create women's fashion in the 16th and 17th centuries!
It might be hard not to snicker at the something called a bum roll, but this foundation garment was critical to creating the fashionable silhouette that women wanted at the time. It is a fairly simple item: they were often made of linen on the outside and were stuffed with wool. The bulk of the material would be in the back and on the sides. There would be ties in the front, creating a flat front. Women were trying to emphasize or even create wide hips, and to do this they wanted their skirts to flair out around the body. This also has the effect of making the waist look smaller.
Busks (or busques) were strips of hard material- think wood, ivory, or whalebone- that sat in the front of the stays to create a flat front. During the 16th and 17th centuries, busks were usually about 10 to 15 inches long. The length would change over time depending on the style of the stays, or later on, the corset. Busks also helped to encourage women to maintain a straight posture. In the 16th and 17th centuries many of them were elaborately carved, as can be seen in the picture below. These were intimate items that were made to fit the wearer, and they would often be carved by husbands or even suitors. Busks continued to be worn with corsets in later centuries.
Source: Fashion History Timeline; Fashion Institute of Technology