Until now, there have been many different opinions of Yangji Nit:, who was the greatest sculptor of the Silla Period, I have summarized my research and opinion of him in this thesis.*br* First, according to my research on the various historical materials, he was not an aristocrat but a commoner. The Samguk yusa 三國遺事 says that his family and birthplace is not known, and this indicates that he must have been a commoner or a lower-class person. If he was an aristocrat, his family and birthplace would have been recorded. In addition, most artists of this period came from the lower-classes whose families and birthplaces were not recorded.*br* Second, it is possible that he studied abroad, but it has to be excluded that he was a foreigner who carne from India or from Western Central Asia. Still there is a small possibility that he had been abroad, but it cannot be verified that he studied abroad because there is not any record about his studying abroad in his biography. Furthermore, the style of his artworks shows that there is no influence of India or Western Central Asia, but some influence of Tang Dynasty China. Therefore, if it is correct that he studied in abroad, it must have been in China.*br* Third, in my judgement two sculptures from Sach'?nwangsa 四天王寺 are of two of the Eight Guardians. In the chapter of "Yangji sas?k 良志使錫" in Samguk yusa. Irv?n wrote that those were Eight Guardians in the base part of a pagoda and these sculptures contain some iconographical similarity with Eight Guardians. We know that Irv?n had profound knowledge of the iconography and characteristics of Buddhist art when we read his description of the Buddhist sculpture in the chapter "Pagodas and Images (塔像)" of Samguk yusa. Therefore, it must be a misunderstanding that he mistook the Eight Guardians for Four Guardians.