"Cuju" flourished during the Song Dynasty (960–1279) due to social and economic development, extending its popularity to every class in society. At that time, professional "cuju" players were popular, and the sport began to take on a commercial edge. Professional "cuju" players fell into two groups: One was trained by and performed for the royal court (unearthed copper mirrors and brush pots from the Song often depict professional performances) and the other consisted of civilians who made a living as "cuju" players. During this period only one goal post was set up in the center of the field.