By the time of the Zhou Dynasty (c. 1046-256 BC) sacrifices at Mount Tai had become highly ritualized ceremonies in which a local feudal lord would travel there to make sacrifices of food and jade ritual items. These would then be arranged in a ritually correct pattern before being buried on the mountain. In the Spring and Autumn period (771-476 BC) the vassal states of Qi and Lu bordered Mount Tai to the north and south respectively, from where their feudal lords both made independent sacrifices on Mount Tai. According to Zhou ritual belief, the spirit of Mount Tai would only accept sacrifices offered by a feudal lord, leading Confucius (in his Analects 3.6) to criticize the ministers who offered state sacrifices here after usurping power. In the ensuing Warring States period (475-221 BC), to protect itself against invasion, the State of Qi erected a wall, the ruins of which are still present today. The name Tai'an of the neighboring city is attributed to the saying If Mount Tai is stable, so is the entire country (both characters of Tai'an, 泰 and 安, have the independent meaning of peace).