They have been made from lead, tin, bronze and from fabric. They might be made by casting with separate or integral shanks, a composite of two sheets of metal or by a bunched scrap of cloth sewn into a ball. Sometimes buttons might have a fabric covering such as silk or a metal covering such as silver
Buttons used during the 15th century (and likely earlier) were sewn onto the edge of the fabric rather than on the face, as we see in modern buttons.
Buttons were common from the 13th century onwards although they are known from earlier finds.