Aak was brought to Korea in 1116 through a large gift of musical instruments from the Song Dynasty emperor Huizong. It remained very popular for a time (there were originally no fewer than 456 different melodies in use) before dying out. It was revived in 1430, based on a reconstruction of older melodies. The music is now highly specialized, and uses just two different surviving melodies, and is played only at certain very rare concerts, such as the Munmyo jeryeak (Sacrifice to Confucius) held each spring and autumn at the Munmyo shrine in Seoul.
Aak is one of three types of Korean court music; the other two are dangak and hyangak. Aak is similar to dangak in that both are rarely played and both have Chinese influences.