Issued in 1360, “Jeong Gwangdo Gyoseo” is currently held at Taesa-myo(太師廟) in Andong(hereinafter the Taesa-myo-held document will be referred to as the “Hyeonjon Gyoseo”). The National Museum of Korea and the National Institute of Korean History each have photographic plates of “Jeong Gwangdo Gyoseo” (the photographic plate of document will hereinafter be referred to as “Geonpan Gyoseo”). Although “Hyeonjon Gyoseo” and “Geonpan Gyoseo” reveals important differences. Particularly notable is the phagspa-character seal “Buma-goryeo-gugwang-in(駙馬高麗國王印)” in “Geonpan Gyoseo.” It is very unlikely that the text with the phagspa-character seal was forged at a later point, which strongly indicates that “Geonpan Gyoseo” is the authentic document. Furthermore, as I investigated the provenance of “Jeong Gwangdo Gyoseo,” it became clear that “Geonpan Gyoseo” was continually held at Taesa-myo at least from the early 17th century until 1935. Various characteristics of “Hyeonjon Gyoseo” strongly indicate that it is a copy of “Geonpan Gyoseo” made in a later period.