This Chinese custom supposedly originated in the 10th century AD when the court dancer Yao Niang bound her feet to resemble the new moon, something the emperor at the time, Emperor Li Yu, greatly enjoyed. The shape and size of the feet, after being bound, was considered highly feminine and was a way for women to attract potential husbands. It also made women walk differently, needing to use their thigh and butt muscles more, which was considered erotic.
Three inch feet were called a "gold lotus" and would likely get you a husband. Four inches, a "silver lotus", was also desirable, but five or more inches, an "iron lotus", and it would be hard to find a suitor.
Foot binding started when a girl was five or six. The feet were first put in hot water, the nails were cut short, and the skin was rubbed with oil before the four smallest toes were broken, folded over, and tied down. The foot would be bent in the middle and tightly tied to break the arch, something the girl would have to facilitate by walking on the bound feet. During this, the heel and sole would be crushed. After about two years the feet would be ready. This tradition lasted into the 20th century.