After the construction of Luoyi, Duke Zhou established a complete hierarchical system, incorporating Yin rituals and adhering to Zhou regulations. It developed into a rigorous hierarchical system of laws and regulations by the middle of the Western Zhou period. Rules were set out to define the number and type of ritual objects used by noblemen in sacrificial ceremonies, social intercourses and banquets. The remnants of vassal states discovered in Henan testify to the ritual system of the Western Zhou Dynasty (1046-771 BC).