Claim: According to the Yongbieocheonga (the first work written in Hangul), Yi Seong-gye was born in 1336 and would later become one of Korea's greatest army generals and kings.
Evidence: Yongbieocheonga literally means Songs of the Dragons Flying to Heaven and was the first work written in hangul. Yi Seong-gye was born in 1335. He had come from a long line of men who had served as government officials familiar with Mongolian customs, he and would later prove to be one of Korea's greatest army generals and kings.