Buttons were invented around 1200, but they were just for decoration. They didn’t actually button anything together. Before 1330 if you wanted a snug-fitting bodice and sleeves, you had to be sewn into your clothing every day by your servant. But around 1330 the functional button came into popular use. Now instead of having to lower a tunic over your head, or sew two sides together, you could have a garment that buttoned up the front, which fit you more snugly.