정호
However, the king continuously called Yi Hwang back and unable to refuse further, he resumed office at the age of 68 and wrote many advisory documents including "Seonghak sipdo" (hangul:성학십도, hanja:聖學十圖, "Ten Diagrams on Sage Learning"). He also gave lectures from the teachings of Song Dynasty Confucian scholars Cheng Yi and Cheng Hao, I Ching, Analects, and Zhang Zai in royal presence. He finally retired from politics at the age of 70 and died in 1570.