And there were many Neo-Confucian philosophers that began to emerge in the late Tang Dynasty, but it's really considered the Song Dynasty where Neo-Confucianism really takes hold. And the most famous of the Neo-Confucian philosophers, sometimes ranked second to Confucius himself in terms of influence on Chinese philosophy, is Zhu Xi. He lived from 1130 to 1200, and he's most known for his, one could say, curation of Confucian texts. He famously curated the four books, Analects of Confucius, Mencius, or The Mencius, by Mencius, Great Learning, Doctrine of the Mean, written by Confucian followers. This curation of Confucian thought, shortly after Zhu Xi's life, it becomes the bedrock of the Chinese education system and the civil service examinations as we go through the Yuan, Ming, and Qing dynasties, all the way to the early 20th century. Now, he also wrote books on tradition and rituals, which are, in some ways, very Confucian because they're focused on the practical, they're focused on the family, they're focused on social cohesion. But he also dabbled in the more spiritual, wrote extensively about notions of Tai Chi, which is really a Taoist or even a pre-Taoist idea, thinking about what is the fundamental nature of the universe, and that Tai Chi itself is the great ultimate, sometimes represented by the yin-yang symbol.