Cheng Hao
In medieval China, the mainstream of neo-Confucian thought, dubbed the "Tao school", had long categorized a thinker named Lu Jiuyuan among the unorthodox, non-Confucian writers. However, in the 15th century, the esteemed philosopher Wang Yangming took sides with Lu and critiqued some of the foundations of the Tao school, albeit not rejecting the school entirely. Objections arose to Yangming's philosophy within his lifetime, and shortly after his death, Chen Jian (1497–1567) grouped Wang together with Lu as unorthodox writers, dividing neo-Confucianism into two schools. As a result, neo-Confucianism today is generally categorized into two different schools of thought. The school that remained dominant throughout the medieval and early modern periods is called the Cheng-Zhu school for the esteem it places in Cheng Yi, Cheng Hao, and Zhu Xi. The less dominant, opposing school was the Lu–Wang school, based on its esteem for Lu Jiuyuan and Wang Yangming.