 Both T’oegye and Yulgok both wrote very specific texts on Sagehood. In 1568, T’oegye wrote Sŏnghak sipto 聖學十圖 (The Ten Diagrams on Sage Learning), and in 1575 Yulgok wrote Sŏnghak chipyo 聖學輯要 (Essentials of the Learning of the Sages). According to Keum Jang-tae (1980 [2000: 40]), author of Confucianism and Korean Thoughts, these texts (the Ten Diagrams and the Essentials) reflect “the two main classical works epitomizing Neo-Confucian learning in the Chosŏn era”. They also embody the development of Korea’s Neo-Confucian tradition. Kim Yung Sik (2017: 25) suggests that