Thought to have begun late in the Tang Dynasty (618-960), the practice of foot binding accelerated during the Song Dynasty (960-1297) and lasted over a thousand years. It started with the wealthy, but quickly spread to lower social classes as well. The ideal bound foot was 3 inches long, the shape of a crescent moon, and covered by a tiny embroidered shoe. Considered the most erotic part of the female anatomy, wives and concubines were selected based on the size and shape of their feet. It took years of intense pain in order to attain this ideal.