The title is a citation from the poem Songs of the Dragons Flying to Heaven. It was compiled as an official affirmation of the Joseon dynasty. The dragons represent the dynasty's ancestors: Mokjo, Ikjo, Dojo, Hwanjo, Taejo (Yi Seonggye), and Taejong (Yi Bangwon). The flight of the dragons is the Joseon dynasty's rise in accordance with "the Mandate of Heaven."
Shares some common characters with the Tree with Deep Roots (2011) (where the action takes place 30-40 years later) but is not 100% prequel to it.