Who was the thinker who advocated the rule of law in the ancient history of China? What major historical event is the background of this thought related to?

Major historical event: a hundred schools of thought contend

BACKGROUND: During the Spring and Autumn Period and the Warring States Period, there were years of wars and social unrest, and drastic changes took place in economy, politics, culture and other fields. When this society is in a period of transition, the "scholars" who master certain cultural knowledge are the most active. They have different attitudes towards change and thinking in different directions, and put forward different plans to govern society and stabilize people's hearts, thus forming a situation in which a hundred schools of thought contend, among which Confucianism, France and Taoism have the greatest influence.