Korean song from Episode 2 at the end of Six flying dragons

Just heard this amazing song at the end of episode 2 of the new Korean drama called Six Flying Dragons and I cannot find it anywhere with the translations. Can anyone give me the name of it? It sounded like a traditional/national song that everyone in Korea would know. The lyrics I know of, are below and the link to the song is: http://www.tiveee.com/ep/six_flying_dragons/?ep=2

at the 55:57 time marker, the song begins. Any help is appreciated!

Lyrics so far:
dance under the moon, view of flowers
the song is joyous
five hundred years of effort and prayer but it is all in vain.

Father is down from a hit with a sword children are ripped apart by taxes.
The sound of mourning is so sorrowful.

what could be different?
why is your cry so mournful?
the ground where a wild flower wilted cannot be found anyway.
A nameless bird, why is your cry so mournful?

nameless bird why is your cry so mournful?

I found out the name of this song - apparently it was just a song the writers of the drama wrote for the drama - it is incredible and called: 무이이야 떼창 (Mui's song)