What is posthumous title of Zhu Xi?

Lu Xun's "From Hundred Herbs Garden to San Tan Yin Yue" begins: "There is a big garden behind my house, which is said to be called Hundred Herbs Garden. Now it has been sold to the descendants of Zhu Wengong with the house ... "A textbook annotation says:" Zhu Wengong, that is, Zhu (1 130- 1200), a philosopher and educator in the Southern Song Dynasty. Zhu Wengong is posthumous title of Zhu. " It is not accurate enough to say that "Zhu Wengong" is Zhu's posthumous title, because only "Wen" is Zhu's posthumous title. "Zhu" is his surname, and there is no posthumous title as "Zhu" in history.