Wikipedia
Yongbieocheonga literally means Songs of the Dragons Flying to Heaven and was the first work written in hangul. It was compiled during the reign of Sejong the Great as an official affirmation of the Joseon dynasty and its ancestral heritage. The Songs, in the form of 125 cantos, were composed through the efforts of a committee of Confucian philologists and literati. This compilation was the first Korean writing to depart from a long history of reliance on Chinese characters and to be recorded in hangul, the first and official alphabet of Korea. Several important themes in addition to that of the establishment of the Joseon dynasty reflect the events that gave rise to the creation of these poems: historical events that took place in China, the apotheosis of virtuous Kings preceding the fall of the Goryeo dynasty in Korea, and the Confucian political and philosophical ideologies of an era that rejected Buddhism.