The majority of early eighteenth century dragon robes that have survived are made of relatively heavy silk brocade. The end of the century, however, the lighter tapestry weave called k'o-ssu and embroidered satin had become more popular. The official dress codes set forth in the Huang ch'ao li-ch' i tu shih states that the tawny yellow color of this robe was reserved for the emperor's sons, excepting the crown prince who was permitted to wear yellow like his father.